Salt curing has been used for centuries to preserve ﬁsh caught at sea. It’s also easy to do at home! Surrounding ﬁsh with a sufﬁcient quantity of salt draws out the moisture; this is called dry brining. But salt doesn’t just dry out the food (along with any bacteria and parasites). At sufﬁcient concentration, dry brining actively disrupts a cell’s ability to function and kills it, rendering bacteria and parasites nonviable.
Traditional Preservatives: Salt & Sugar
Pizza Dough—No-Knead Method
How to Cook a High-Heat Pizza
A serious examination of pizza is clearly a must-have for a book called Cooking for Geeks. Pizza covers so many variables: flavor combinations, Maillard reactions, gluten, fermentation, moisture levels, and temperature. We’ve covered most of these elsewhere in the book, but we haven’t yet talked about temperature, which is key to a good crust.
Great thick-crust pizzas have a great interior that comes from good dough that’s baked at moderate temperatures. My local delicious thick-crust pizza place runs its oven at 450°F / 230°C in the winter, 350°F / 180ºC in the summer. (The oven can’t be run any hotter in summer without the kitchen becoming unbearable; they just bake the pizzas longer.) Easy enough.
But if you want to make a crispy thin-crust pizza, high heat is critical for creating a great crust. The lower temperature bound I’ve found acceptable for great flat-crust pizza was 600°F / 315°C. At 700°F / 370°C, the crust becomes noticeably better. The best thin-crust pizzas I’ve had were cooked in wood-fired brick ovens or on a grill over wood charcoal with temperatures running between 750°F / 400°C and 900°F / 480°C. Sadly, most ovens max out at 550°F / 290°C, making great thin-crust pizza hard to do in the oven. What’s a thin-crust pizza-loving geek to do? If only there were a flow chart for this…
The Sweet Way To Calibrate Your Oven
The Two Things You Should Do to Your Oven RIGHT NOW
One piece of equipment that you’re probably stuck with is your oven. What makes an oven “good” is its ability to accurately measure and regulate heat. Since so much of cooking is about controlling the rate of chemical reactions using heat, an oven that keeps a steady temperature and isn’t too cold or too hot can make a huge difference in your cooking and baking. There are two things you can do to make sure you get the best results with what you have:
Calibrate your oven. Get a digital probe thermometer and check that setting your oven to 350°F / 180°C actually lines up with the thermometer, placing the thermometer in the same location in the oven as your baked goods are going to go. If the temperature is way off, check to see if your oven has either an adjustment knob or a calibration offset setting. Otherwise, keep in mind the offset when setting temperatures. Your oven will cycle a bit above and below the target temperature—the oven will overshoot its target temperature, then turn off, cool down, turn back on, and so on. It’s possible that your oven could be correctly calibrated but measure too hot or too cool, so check the thermometer several times over a span of 10 minutes.
Improve your oven’s recovery time and even out the heat: always keep a baking or pizza stone in your oven. Say you’re baking cookies: oven set to 375°F / 190°C, cookies on pan, ready to go. In an empty oven, the only thing hot is the air and the oven walls, and opening the door to pop the cookies in leaves you with just hot oven walls. You’ll get much better results by keeping a baking or pizza stone on the very bottom rack in your oven. (Don’t place the cookie sheet directly on the pizza stone!)
The baking stone does two things. First, it acts as a thermal mass, meaning faster recovery times for the hot air lost when you open the door to put your cookies in. Second, if you have an electric oven, the stone serves as a diffuser between the heating element and the bottom of your baking tray. The heating element emits a hefty kick of thermal radiation, which normally hits the bottom side of whatever bakeware you put in the oven. By interposing between the heating element and the tray, the stone blocks the direct thermal radiation and evens out the temperature, leading to a more uniform heat. Buy the thickest, heaviest stone you can. Like any thermal mass, a stone will add lag to heating up the oven (and cooling it down— that’s the point!), so make sure to allow extra time to preheat your oven.
Check back next week for the Lab: The Sweet Way To Calibrate Your Oven.
Winter White Bean and Garlic Soup
In a bowl, soak for several hours or overnight: 2 cups (400g) dry white beans, such as cannellini beans. After soaking them, drain the beans, place them in a pot, and ﬁll it with water (try adding a few bay leaves or a sprig of rosemary). Bring the water to a boil and simmer the beans for at least 15 minutes. Strain out the water and put the beans back in a pot (if using an immersion blender) or in the bowl of a food processor. Add to the pot or bowl with the beans and then purée until blended:
- 2 cups (480 mL) chicken or vegetable stock
- 1 medium (100g) yellow onion, diced and sautéed
- 3 slices (50g) French bread, coated in olive oil and toasted on both sides
- ½ head (25g) garlic, peeled, crushed, and sautéed or roasted
- Salt and pepper, to taste
• Don’t skip boiling the beans. Really. One type of protein present in beans— phytohaemagglutinin—causes extreme intestinal distress. The beans need to be boiled to denature this protein; cooking them at lower temperatures (e.g., in a slow cooker) will not denature the protein and actually makes things worse. If you’re in a rush, use canned white beans; they’ll have already been cooked.
Variations: try blending some fresh oregano into the soup. Toss some bacon chunks on top or grate on some Parmesan cheese as well. As with many soups, how chunky versus how creamy to blend the soup is a personal preference.
My friend Dawn hates the taste of eggs. As a little kid, she ate eggs that had been cooked in burnt butter. Her brain linked the revolting acrid taste of the burnt butter with the taste of eggs, and to this day that link is stuck in the basal parts of her brain to the point that she can’t eat eggs. A taste aversion—a strong dislike for a food, but not one based on an innate biological preference—typically stems from prior bad experiences with food, often occurring in childhood like Dawn’s burnt-butter eggs experience. A foodborne illness is a common cause.
Taste aversions are fascinating because they’re entirely learned associations. The food that triggers the illness is correctly identiﬁed only part of the time. Typically, the blame is pinned on the most unfamiliar thing in a meal, known as sauce Béarnaise syndrome. Sometimes the illness isn’t even food-related, but a negative association is still learned and becomes tied to the suspected culprit. This type of conditioned taste aversion is known as the Garcia effect, named for psychologist John Garcia, who determined that he could create taste aversions in rats by invoking nausea when they were exposed to sweetened water. As further proof that we’re at the mercy of our subconscious, consider this: even when we know we’ve misidentiﬁed the cause of an illness (“It couldn’t be Joanna’s mayonnaise salad—everyone else had it and they’re ﬁne!”), an incorrectly associated food aversion will still stick.
Sometimes only a single exposure that results in foodborne illness is all it takes for your brain to create the negative association. One of the cleverest examinations of taste aversion was done by Carl Gustavson as a grad student stuck at the ABD (all but dissertation) point of his PhD. Reasoning that taste aversion could be artiﬁcially induced, he trained free-ranging coyotes to avoid sheep by leaving (nonlethally) poisoned chunks of lamb around for the coyotes to eat. They quickly learned that the meat made them ill, and thus “learned” to avoid the sheep. As tempting as it may be, I don’t recommend this method for kicking a junk food habit, but it does hold an odd appeal.
What can you do to overcome a taste aversion? To start with, you have to be willing and open. You may feel that eggs are disgusting, and if you’re unwilling to unwire that association, your chances of eating an omelet are rather low. Repeated exposures to small quantities of the offending item, in situations where you feel comfortable, will eventually remove the association between the food item and negative memory (called extinction). Remember, start with small quantities and use consistent repeated exposures in a supported environment. If it’s too much at ﬁrst, try changing some aspects of the food, such as its texture or the cooking technique, so that the ﬂavor association isn’t as strong.
*See Also: What is Flavor: A Lesson in Orthonasal Olfaction
What is Flavor – A lesson in Orthonasal Olfaction
Flavor is a Jedi trick of the mind, a combination of the gustatory sense of taste and the olfactory sense of smell that your brain fuses into a new sensation. To give you an idea of just how clever your brain is about flavor, consider this: your brain detects odors differently based on whether you are breathing in or out. This is crazy! It’s like saying swiping your hand left to right on a cold countertop causes you to feel temperatures differently than swiping right to left. Our brains are wired to process smell signals in two different ways; flavor uses the second way.
Some definitions will make this easier to discuss. Orthonasal olfaction is defined as what your nose detects from sniffing something that exists in the world. Sniffing a rose, unless you’re also chewing it, uses the orthonasal route for smell. Retronasal olfaction is what your nose detects in the foods you eat when air is taken in from the mouth and circulated up to your nasal cavity. Even if you don’t notice it happening, it is! Try chewing food with your nose pinched: cut off the airflow, and poof, the flavor sensation’s gone.
To unravel this trick of the brain, a researcher, Paul Rozin, gave subjects unfamiliar fruit juices and soups via the orthonasal route—“Here, sniff this; remember this odor”—and then gave the foods to the subjects again via the retronasal route (through a plastic tube), asking them to identify the previously remembered odor. They did horribly. Same compound, same sensory apparatus, completely different experience. As I promised, smell is simple in the abstract but complicated in the details, so it follows that flavor is no different.
From a practical perspective, which flavors you’ll like or dislike is a matter of exposure and preference. Rozin started studying the orthonasal and retronasal issue when stumped by stinky cheeses—how is it that we have a different experience of flavor for something that smells disgusting? There’s a lot that psychologists and physiologists are still exploring. Fortunately, you needn’t be one to cook a good meal. When working with food, keep in mind that flavor is a specific combination of the two senses of taste and smell, but not a straightforward summation of the two. Taste the food to adjust its flavor before serving it! Smelling alone isn’t enough.
Here are some tips for great flavor when cooking:
- Chew! Admittedly an odd suggestion for good flavor, chewing food crushes, mixes, and kicks up a bunch of compounds for your olfactory system to detect, adding smells that fold into flavor sensation. Remember, for a compound to activate an odor receptor, it has to be present at the point of detection. This raises the question: does chewing food with your mouth open lead to a different flavor experience? (If animals always chew with their mouths open…)
- Use fresh herbs. Most dried herbs have weaker flavor because the volatile oils that are responsible for the aromas oxidize and break down, meaning that the dry herbs are a pale substitute. Dried herbs have their place, though; it makes sense to use them in the dead of winter when annual plants like basil aren’t in season. Store dry herbs in a cool, dark place (not above the stove!) to limit their exposure to heat and light, which contribute to the breakdown of organic compounds in spices. Grind your own spices. Don’t used preground black pepper; it loses much of its flavor over time as many of the volatile compounds change. Fresh-grated nutmeg is also much stronger than preground nutmeg. The aromatics in a preground spice will have had time to either hydrate or oxidize and disperse, resulting in flavor changes. Most dried spices also benefit from being bloomed—cooked in oil or a dry skillet under moderate but not scorching heat—as a way of releasing their volatile chemicals without breaking them down.
- Don’t discount frozen ingredients. Commercially frozen vegetables and fruits are convenient and work fine in some dishes. Freezing produce right when it is harvested has advantages: nutritional breakdown is halted, and the frozen item is from the peak of the season with maximal flavor (whereas the fresh version in your store may have been harvested early or late). Frozen produce is especially useful if you’re cooking for just yourself: you can pull out a single portion as needed. Want to freeze your own crop or a surplus from a CSA (community-supported agriculture) food share? See page 365 of my cookbook (you can buy it here) for how to use dry ice. (Freezing in your home freezer takes too long and leads to mushy veggies.)
- Use alcohol in cooking. My favorite restaurant in San Francisco uses kirschwasser in its fruit soufflés, and adding a splash of wine in sauces or to deglaze a pan to make a quick sauce is standard practice. Using alcohol changes flavors because of its chemistry: it takes the place of water molecules normally attached to compounds, resulting in lighter molecules that are more likely to evaporate, and with higher evaporation rates there are more volatiles for your nose to detect.
*See Also: Taste Aversions
Gluten Free Diets: Fad or Science?
Interest in eating gluten free has seen a major uptick in the past few years, but how much does the science back up the claims?
First, some numbers. I spoke with Darren Seifer at the NPD Group earlier this summer. During our conversation he shared some numbers with me from their annual research of consumer behavior around food and beverage:
“Most people who are trying to avoid gluten don’t need to. They don’t have celiac; less than 1% of Americans have celiac. It’s estimated that another 6-7% of people have some kind of sensitivity to gluten. There’s only about 8% who have some kind of sensitivity to gluten. At the same time, 30% of people are telling us that they are trying to avoid gluten. Most of the people are avoiding gluten for reasons other than some need. The reasons that they are telling us is that they feel better, or that they feel it’s healthier even when isn’t necessarily. But that’s the predominant reasons that we’re getting: they just feel better when they avoid it.
That 8% of a population is sensitive to gluten is huge. Having more food options for these individuals is fantastic. We’ll all benefit from a better understanding of what causes these health issues and new processes created for making gluten-free food won’t be limited to just the gluten-free eater. (Side note: 8% may be high—I’ve seen 0.5%—but there will be a difference if one study is looking at gluten in isolation and another is looking at it in context. It may be that for 8% of us, gluten triggers a response to something else we’re eating—see this study.)
But what about everyone else? Depending upon the report*, somewhere between 24% (30%-8%) and 39% of Americans claim gluten sensitivity. (*Another report, mentioned by NPR’s The Salt, claims 47% of Americans identify as gluten-sensitive, so that 24% “self-report but not diagnosed” might be more like 39%.)
I suspect that 24-39% (can we just call it “one third?”) of the American population who incorrectly claim gluten sensitivity—excluding those who have a measurable physiological response—fall into one of the following categories:
- Placebo effect—believing that the food is better for you may in fact make the food better for you. There are plenty of anecdotes of this; I’d be grateful for readers aware of good stories and studies that relate to food (please contact me with them!).
- Perceptions around health—related to placebo effect, but more of a “health halo.” Ironically, eating gluten-free can cause long-term deficits in trace nutrients normally obtained from flour (iron, thiamin, folate, vitamin A, etc.); fortified gluten-free foods may be in order.
- Distrust of the food system—i.e. who controls our food system, corporate monopolies on patents, monocultures / non-suistanable farming. There are very important issues here, but they’re outside my domain of knowledge. In conversation with readers, people bring up fears that “modern wheat” has been genetically altered and is unhealthy, or that modern baking practices use shorter ferment times for yeast to “fully convert” the wheat. I’ve seen this pattern before in conversations about GMOs; I have found that the science–based fears are generally masking concerns around food policy issues.
- Sense of community—there must be a New Yorker cartoon out there with a college student showing up to a protest with a blank sign and a pen, asking “What are we protesting this time?” Being part of a tribe is empowering. From weight loss to smoking, the behaviors you perform are shaped by your peers. I’d be fascinated to see a study on correlation of when individuals start claiming gluten sensitivity based on when their friends did.
What I find fascinating is the perception around gluten-free. Why do we eat the way we do? Where do we get our beliefs about our food from? (The placebo effect fascinates me.) How can we learn to set aside personal beliefs so we can correctly apply the science? Let me know your thoughts.
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Comments of Note that I’ve Received:
- There’s also a known effect that *any* food restriction will make most people eat better, because they have to pay attention. e.g. people who eat a lot of junk will legitimately feel better gf, because they can’t just grab a doughnut today. It’s essentially the same as the “any diet works” trick for non-calorie counting stuff. —@MagpieChristine
- Open Question: differences between FODMAP and gluten sensitivity. See this study for more about FODMAPs. Some individuals may be sensitive to FODMAPs (short chain carbs & co.) but think it’s gluten causing the problem.
- One reader calls into question the 8% figure — the paper I link to has a very small sample size (37 subjects), but Darren’s figure is also in that same range. His data was based on the NPD Group’s annual report, I believe, but I’d like to find more data on this stat!
Two Fun DIY Projects: Vanilla Extract and Liquid Smoke
Last Friday, I was on Science Friday chatting with Ira Flatow about some fun do-it-yourself things you can do at home from the second edition of Cooking for Geeks.
I already wrote up instructions for my DIY Bittersweet Chocolate Bar; in this post I’ll share details for how to make homemade vanilla extract as well as DIY liquid smoke. Spoiler: vanilla extract is super easy; liquid smoke is super hard. These two projects are great examples of solvency, and liquid smoke demonstrates how to do what chemists call dry distillation. Science! Bam!
First, here’s the interview, courtesy Soundcloud. Scroll down for the geeky science details.
How to Make Vanilla Extract
Instructions: Slice open a few vanilla beans (shop online for the cheaper grade B ones), drop them into a small container, and top off with vodka. Wait a few weeks and you’ll have vanilla extract. The strength of the extract will depend on the vanillin levels, which will depend on the specifics of the vanilla beans and how many used. You’ll need to experiment and adjust quantities when using your DIY Vanilla Extract in cooking.
Why this works: Different compounds are soluble in different solutions. In cooking, we use three primary solvents: water, lipids, and alcohol. Each works on different types of compounds, so matching the chemistry of the solvent to the chemistry of the volatile compound is the key to making good extracts. The same chemical principle that allows water to dissolve compounds also applies to lipids and ethanol, so which solvent to use depends on the structure of the compounds being dissolved. In the case of vanilla, alcohol (a.k.a. ethanol) works the best. If you’re making extracts from other items, you may find water or lipids work better. This is why hot peppers are sometimes infused in oil—the capsaicin dissolves better with lipids (“like dissolves like”) due to the compound’s chemical structure.
One P.S. on my explanation: most compounds are more complicated than this abbreviated explanation implies. It’s not that vanillin or capsaicin can’t dissolve in water; but the solubility is much lower than in ethanol or fats. This is why capsaicin, without any lipids around, can still dissolve into water.
How to Make Liquid Smoke
Instructions: Download my lab for How to Make Liquid Smoke (PDF). Warning: it’s a long and complicated project. Liquid smoke involves similar concepts as vanilla extract—solubility of compounds in liquids—but is much more complicate.
Why this works: To make liquid smoke, you need to heat wood chips to a temperature high enough for the lignins in wood to burn (around 752°F / 400°C), pipe the resulting smoke through water, and do so without any oxygen. The water-soluble components of smoke remain dissolved in the water, while the non-water-soluble components either precipitate out and sink or form an oil layer that oats and is then discarded. The resulting product is an amber-tinted liquid that you can brush onto meats or mix in with your ingredients. I do NOT recommend using your own DIY Liquid Smoke, except perhaps once as a curiosity project.
Do NOT make liquid smoke by soaking “smoked” wood chips in water. Properly made liquid smoke filters out many mutagenic, cancer-causing compounds; the DIY instructions I typically see concentrates those compounds into what you’re eating.
Incidentally, the wood chips turn into charcoal in the process; they’re carbonized, but without oxygen present, they can’t combust. You can create your own charcoal by sealing up wood chips inside a container that will vent out smoke but not circulate air back in. You can also make charcoal from materials besides wood. I know one chef who uses leftover corn cobs and lobster shells to create “corn cob charcoal” and “lobster charcoal,” and because some of the flavor molecules from those items are extremely heat-stable, using the charcoal for cooking imparts a whiff of those flavors as well.
DIY Bittersweet Chocolate Bar
Psst… I’ll be on Science Friday today to talk about this and more — tune in at 3:40 pm Eastern Time! -Jeff
A bar of dark chocolate is amazing—but it wasn’t always this way. Back in 1879, a Swiss entrepreneur by the name of Rudolph Lindt invented a refining process call conching that took gritty, granular chocolate and turned it into the deliciously smooth bars that we enjoy today.
When working on the second edition of Cooking for Geeks, I wondered: what was chocolate like before Lindt’s discovery? And just how hard is it to conche your own chocolate?
Let’s start with fun trivia about the components of chocolate before digging into a simple do-it-yourself version:
- Cacao Nibs are the dried, fermented seeds of the cacao plant.
- Language geeks: Note the spelling: cacao vs cocoa. Cacao generally refers to parts of the plant and cocoa refers to edible food products. The letter transposition likely occurred in 1755 by dictionary maker Samuel Johnson on page 401 due to the Spanish spelling.
- Old-fashioned Coca-Cola bottles, with their ribbed shape, are a reference to cacao pods—inspiration by proximity in the dictionary; the cacao tree has nothing to do with coca bush.
- Cocoa butter, a.k.a. cocoa fat, is the fat from the cacao nibs. Sometimes we forget: plants have fats!
- Fats are triglycerides; in the case of cocoa fat, the most prevalent triglycerides are myristic, oleic, and palmitic acid. Butter—as in cow, not cocoa—has a very similar fat composition, hence the similarities in melting temperatures.
- The exact ratios of the triglycerides in cacao seeds will depend on the climate in which the plant lives. Cooler climates (i.e. higher elevations or geographic variations) will create a fat composition that has a lower melting point.
- Cocoa butter tastes sorta like shortening. It’s not that delicious.
- White chocolate is cocoa butter, sugar, and often flavorings like vanilla. Technically it is chocolate—it has parts of the cacao plant—but some may disagree.
- Cocoa powder is the dried, dark solids of the cacao nibs—hence it’s sometimes call cocoa solids.
- If you’re a baker and have wondered what Dutched cocoa powder is: it’s cocoa powder processed to improve solubility (it’ll mix better—it’s more hydrophilic) and alter its flavor. (The Dutching process raises the pH of cocoa powder, which is why Dutched cocoa powder shouldn’t be substituted for regular cocoa powder in baked goods that rely on it to react with baking soda.)
- Bittersweet chocolate is the combination of cocoa fat, cocoa powder, and sugar. Sometimes flavorings like vanilla are added in; sometimes emulsifiers as well.
- There’s no legal definition specific to bittersweet chocolate, but as a guideline, bittersweet chocolate is typically 30% cocoa fat, 40% cocoa powder, and 30% sugar.
- When you see a bar of chocolate that says “70% bittersweet chocolate,” that’s the amount of cocoa fat and cocoa powder. One manufacturer’s 70% might be 30% fat, 40% powder; another’s could be 35% fat, 35% powder. Because cocoa powder is bitter and cocoa fat is not, a 70% bar made with more cocoa powder and less cocoa butter will taste more bitter, even though both bars are “70% bittersweet.”
Ok, so hopefully that clears up some common confusion around spellings, differences in ingredients, and other “base knowledge” parts of chocolate.
Ok, great—so how do I make a bar of delicious bittersweet chocolate?
- Take the cacao nibs, warm them, and slowly grind them for many hours. The fats in the seeds will melt, and the other parts of the seeds will get ground up and suspended in the fat. This, by the way, is called chocolate liquor. It’s bitter—no sugar yet.
- Add sugar and conche. Conching does a bunch of things: breaks up the sugar, thoroughly distributes the ground cocoa solids, and slowly aerates and oxidizes some compounds from the chocolate. Conching is a slow process—6 hours seems to be the shortest time I’ve read; some makers reportedly let chocolate conche for ~72 hours. Longer = smoother, but also more expensive.
But wait, Jeff, I don’t have a conching machine… there must be another way?!
There is, sort of. If you don’t mind skipping the conching, you can make a bar of chocolate that’s unconched. You won’t be rushing out to buy it, though—before Lindt’s improvements, chocolate was generally used as an ingredient in food and drinks, not as a consumable itself.
Still, it’s fun to see what chocolate would have been like before the modern improvements.
For a FULL do-it-yourself experience, you could start with cacao nibs and sugar, heat, grind, and labor away. But we can take a shortcut, albeit unfaithful: cacao nibs are processed into cocoa powder and cocoa fat, so we can use those instead.
Here’s how to make a sample of Unconched Bittersweet Chocolate:
- In a small bowl, melt 1 tablespoon (9g) of cocoa butter, either in a pan of simmering water or the microwave.
- Remove the butter from the heat or the microwave and add 2 teaspoons (10g) of sugar and 2 tablespoons (12g) of cocoa powder.
- Using a spoon, mix thoroughly, stirring for 1–2 minutes.
- Transfer the mixture to a flexible mold or parchment-paper- lined container and allow it to cool.
You’ll notice when tasting this chocolate that the initial flavor is astringent and bitter, followed by a sweeter, possibly floral taste as the sugar dissolves in your mouth. Using superfine sugar instead will give a smoother texture, but the chocolate won’t have the same mouthfeel as the bars we are used to, which are conched and tempered.
Speaking of tempering: I’m skipping the details of that here, but for the curious, read pages 158-160 (PDF).
P.S. Here’s what an industrial conching machine looks like:
Popcorn on a Cob
A cute video about popcorn, Pop On A Corn, has been exploding all over the internet, but it’s a hoax. But it’s so close to what can be done that… well, argggh!
The hoax video inspired me to attempt my own version, using REAL popping corn. With a time limit of 2 hours for shooting and 2 hours for editing, here’s a quick pass at a fun video on REAL pop corn on cob.
Can You Cook an Egg in the Dishwasher?
I had a reader ask if you can poach an egg in a dishwasher. It’s an interesting cooking hack and the answer isn’t obvious.
In theory, it should be possible. Eggs held at 140—144°F / 60—62.5°C for long enough will begin to set; this is the concept behind sous vide cooking. Here’s the chart for this from the second edition of Cooking for Geeks:
Dishwashers have heating elements and can get hot enough. In practice, though? It is doable—others have pulled it off. But the directions call for adding boiling hot water, and while an awesome breakfast party trick, I wanted to see if a straight-up attempt would work, using the high-heat cycle of the dishwasher I have on hand.
I’d be curious for others to try this and let me know what results you get!
Appleless Apple Pie
This may look like an Apple pie — and it sure tasted like one — but no apples were harmed in the making. Mock Apple Pie, as it’s traditionally called, dates back to at least the 1850s and is a great example of how expectations play into our perceptions.
Mock apple pie relies on cream of tartar for the acidic kick normally provided by malic acid in apples. Crackers are soaked in sugar syrup for sweetness and texture (cooked apples and soggy crackers have similar texture). Lemon juice, vanilla, cinnamon, and nutmeg add enough of the flavors we associate with apple pie to fool an eater.
For more, see this Newsweek article that I’m feature in. For a recipe, check out page 96 of the second edition of Cooking for Geeks [pdf]. Let me know if you make it, and how it goes when foisting off on unsuspecting guests!
Beer Mile: Four Beers, Four Laps—Why?!
This last weekend, a friend of mine invited us to her friend’s “Beer Mile.” Four cans of beer, four laps, one mile—for one Why did I think that was a good idea? experience.
I opted to watch instead, and used it as an opportunity to play with iMovie. I’m impressed at how much easier video work has become in the last few years!
Instead of Thanksgiving cooking tips (cook the turkey breast separate from the turkey legs!) or sharing more about the new second edition of Cooking for Geeks, I present: Beer Mile.
Popcorn and the Ideal Gas Law, PV = nRT — The Science of Popcorn!
Did you know popcorn pops at roughly nine times atmospheric pressure? The inside of a popcorn kernel is about ~13% water. When that water heats up—trapped inside the confined space of the kernel’s pericarp—the pressure goes up until the pericarp ruptures and the insides, now melted, spew out.
You’ve probably never thought about the physics of popcorn, or even what temperature popcorn pops at. Snag some oil, a digital thermometer, and a pan. Try popping some popcorn kernels at various temperatures. You’ll soon figure out that popcorn doesn’t really pop well until ~350°F / 177°C. (For photographs, see page 307 of the second edition of Cooking for Geeks—click for free PDF of that page.)
But how do we know popcorn kernels rupture at nine times atmospheric pressure? Because as temperature changes, the volume of a gas changes, and knowing popcorn kernels are roughly 13% water allows us to use the ideal gas law (click to see UC Davis’s ChemWiki entry), which is:
PV = nRT
What I didn’t include in the second edition of Cooking for Geeks was any discussion of the ideal gas laws—it didn’t seem culinarily useful, even if the geek in me loves these sorts of details. An old magazine, The Physics Teacher, has a lovely writeup on The Physics of Popping Popcorn from April 1991. Thankfully, things like the laws of thermodynamics haven’t change much in the last… oh, ever. If you’re teaching science, or want to really geek out, check out his writeup for details.
P.S. Our CSA share last week included 4 popcorns-on-the-cob—popcorn corn is a variety of corn that has a really tough pericarp. That’s what the photo up top is of!
How They Printed Books in the 1940s
If you’re a book lover and a geek, spend ~10 minutes to watch this lovely video from the 1940s about how books were made.
Here I am, ~70 years later, marveling at how things have changed. So that’s where the phrase “put to bed” comes from!
Partway through the video, I wonder what book they’re printing. There’s a single clip of a person checking the page numbers are in sequence: 1… 3… 5…
I pause the video, go to books.google.com, and type in the two phrases that I can see: “of Fair Luna” “with inimitable”
One match. From 1947.
This is amazing. Isaac Asimov futuristic amazing. How would he have described what I just did? Sitting at home, pulling up a video from a digital archive, glancing at a few words and searching the vast databanks of human knowledge for an answer? I imagine Asimov would have written the scene with me making a cup of coffee while I wait for the digital systems to search for an answer. My wait? Under a second. Something to keep in mind when I swear at the computer for not being able to upload an image to Twitter…
P.S. The book that was printed in that video? On Amazon…
Why Can’t We Just Eat Grass?
A friend of mine who works in food policy, talking with random member of the public:
Random person: Why can’t we just eat grass?
Friend: Because we aren’t cows.
Random person: But I’m a vegetarian.
Ingredient Labels—Watch Out for This One Trick!
I wrote this up a few years ago but let it languish in my “thoughts” pile—clicking the “publish” button at last. Following up on yesterday’s comments about the US FDA’s proposal to change the food label by adding “added sugars” with a percent daily value is this below gem. I’m not sure it’s going to make much of a difference, although it’s a step in the right direction.
Naked Juice makes a “green machine” drink with “10 green turbo-nutrients”. Take a look at this screen grab of “the boost inside” a bottle—notice anything?
Hint: the qualities of the ingredients are given in mg. Not grams, but milligrams. 100 mg of broccoli = 0.1 g of broccoli.
Here is what 100 mg of broccoli looks like:
This can’t really be right, can it?
Emails to Naked Juice below.
Hi, I purchased a bottle of ”Green Machine” today and was wondering about the ingredients used in it. On the back side of the label, it says the quantities of fruits and ”boosts” inside, such as 100mg of broccoli. Is that 100mg of straight-up, good ol’ fashioned broccoli, or 100mg of some sort of extract or flavor? Thanks!
Thanks for your inquiry about broccoli in Green Machine. The broccoli boost is from broccoli and is not a natural flavor extracted from broccoli.
We appreciate your business, Jeff, and I hope this information is helpful.
Naked Juice Consumer Relations
Thanks for your reply! So to confirm, when the label says “50mg parsley”, that means there’s literally 50 mg of parsley in the bottle?
Thanks for your inquiry about the Green Machine label meaning that there are literally 50 mgs. of parsley in the bottle .
Yes, that’s correct! We follow all FDA labeling regulations and as you can see by the ingredients list, parsley and broccoli are actual ingredients in the Green Machine.
What am I missing?
Sugar Recommendations—And What We’re Missing About Them
Today’s New York Times has a Well Blog post on the FDA’s proposal to change how sugars are labeled in foods. There’s lots that can be said about this (primarily “Yay!”), but here are some quick thoughts about what I think people are missing about the sugar recommendations.
- Are you aware that the current food labels in the United States that say stuff like “Total Fat 4.5g 3%” don’t list a percentage for sugar? Most of my friends, when I point this out, don’t believe it. (Inattentional blindness.) Go check it out—snag a container of something and look at the food label.
- The U.S. FDA’s proposed labeling law would require food labels to list a “percent daily value” on a line of “Added Sugars”, similar to the other lines already there. That’s it. Small change; big fuss from industry.
- Forcing food companies to list “added sugars” (i.e. doesn’t include sugars present from ingredients like fruit), in my opinion, will lead to food companies changing the ingredients in manufactured foods. My bet is we’ll see a decrease in added sugar and an increase in things like fruit puree, without any real change in health outcomes.
While there’s lots of evidence that bad diet and obesity go hand-in-hand, don’t jump up and down thinking that by avoiding junk food and “added sugar” foods that you’re healthier. It’s your overall diet that matters. Brian Wansink’s Food & Brand Lab at Cornell University has an interesting study out last month that claims junk food and fast food aren’t correlated with obesity (David Just and Brian Wansink (2015). Fast Food, Soft Drink, and Candy Intake is Unrelated to Body Mass Index for 95% of American Adults. Obesity Science & Practice, forthcoming). I ran it by one well-respected nutritionist and her reaction was to agree: “the overall diet is what counts.”
P.S. If you’re curious for more thoughts on sugar, see Marion Nestle’s blog post from today.
Does Baking Soda Make Omelets Fluffier?
I’ve found a few recommendations floating around the internet that suggest you could use baking soda to make fluffier omelets, to tenderize meat or even as an additive to beans to reduce “bean bloat”. Do you know if there might be any truth to these? If so, why would they work? I’d also love to know if you have any other ideas for unexpected ways someone could use baking soda in cooking.
Hi Jade —
Both baking soda and baking powder can be mysterious, but they’re actually pretty easy to understand once you view them with some science in mind.
First, baking soda: it’s a single compound — sodium bicarbonate — that reacts with other ingredients and produces carbon dioxide. When sodium bicarbonate gets added into your other ingredients, it dissolves into just sodium and bicarbonate. The sodium adds a salty taste (just like sodium chloride does), but it’s the bicarbonate that’s useful: it can react with other acid compounds (vinegar, lemon juice, buttermilk) to generate gas, or when heated up, will break down on its own and generate carbon dioxide.
Baking powder is like baking soda, but is made of more than one compound. It’s what I call a “self contained leaving system” — it’s got everything you need to lighten food. Baking powder is usually composed of baking soda and an acid such as cream of tartar or monocalcium phosphate. Add water, and poof! The ingredients dissolve and can react with each other. (In powder form, they don’t interact very quickly — but can, over time — so if your baking powder is a few years old, it won’t work very well.)
So now that we have the definitions out of the way, what can we do with them? Baking soda, as a single compound, can be used anywhere there the chemical reaction between the bicarbonate and another compound leads to a change. (Of course, if you add too much baking soda, it won’t completely react — there’ll be left over baking soda that then interacts with your taste buds and tastes nasty.)
You’d asked how baking soda would make an omelet fluffier. Eggs are surprisingly basic; I wouldn’t think of them as having acids that the baking soda can react with. Baking soda does decompose into carbon dioxide and water with heat, though — it looks like this begins around the boiling point of water — so it’s possible that that would be a mechanism. Honestly, though? If I wanted a light, fluffy omelet, I would separate the eggs white and the egg yolks, whisk the egg whites some, and then mix the yolks back in. “Fluffy” means air, and using baking soda is just one way of doing it (chemically). You can “add” air in mechanically, and avoid the potential change in flavor from the baking soda.
As for adding baking soda to beans: according to the US Dry Bean Council — this is a private industry group of folks who grow and sell beans — adding baking soda will make beans more tender (which you’d only want to do if your beans are coming out too tough). They don’t mention anything about baking soda and bloat; however their answer on “gas-causing properties of dry beans” looks reasonable, See: www.usdrybeans.com/nutrition/nutrition-facts/
You might skim books.google.com/books?id=yb4B-19xm-MC and books.google.com/books?id=at4WAwAAQBAJ — I don’t know how much I’d trust these, since they’re recent ebook of low quality, but it’s an interesting place to see what’s commonly believed (true or not) that you might be able to then dig into. For example, baking soda in the fridge to absorb odors is not something that I believe works — and here’s a link to “Ask a Scientist” saying as much at the Department of Energy (who I would believe): www.newton.dep.anl.gov/askasci/chem00/chem00388.htm
Hope this helps! I’m going to wander off to my kitchen to make two different omelets — one with baking soda — to see if there’s any truth to the idea.
Troubleshooting Turkey on Science Friday
Just a brief note to say that I’ll be on Science Friday this Friday around 2:30 PM ET / 11:30 AM PT, talking with Ira Flatow about Thanksgiving and how science can help you avoid disaster. Listen in and tweet your questions at us at @scifri !
…and that’s a wrap. If you missed it, you can listen to How To Avoid ‘Food Failures’ This Thanksgiving, online now.
Thoughts on GM Grass Killing Texas Cattle
CBS News ran a story titled “GM grass linked to Texas cattle deaths” earlier today. In a nutshell, the story reports that 15 cows died from cyanide poisoning after eating genetically modified grass. See www.cbsnews.com/8301-201_162-57459357/gm-grass-linked-to-texas-cattle-deaths/ for more.
There’s a pretty clear culprit, from the reporting thus far: cows die from cyanide poisoning, grass tests positive for cyanide, so the grass did it. If I were on the jury, I’d definitely vote guilty. But why start the headline with “GM grass”?
Questions I Have:
How often do plants produce compounds that can lead to cyanide poisoning? The story sounds horrific: Fields of cyanide gas… animals passing out… queue WWII flick… (Or Wizard of Oz?) But plenty of plants produce toxins like cyanide to keep themselves from being eaten. A quick Google search for “cyanide grass” and a quick peak on pubmed for cyanide poisoning shows a few interesting things, among them: “Southeastern plants toxic to ruminants: Selected toxic plants affecting cattle, sheep, and goats in the southeastern United States are presented…” (I really hate paywalls on journals, by the way.)
For cyanide specifically, I know that some seeds (like apple seeds) contain trace amounts. It’s not unnatural for plants to produce these types of compounds. Skim through www.aces.edu/pubs/docs/A/ANR-0975/ANR-0975.pdf — there are plenty of plants that rank right up there with things I’d suggest skipping. (Anyone know the writers for House M.D.? They should check out a plant called white snakeroot: cows can tolerate eating it but the milk they then yield can kill humans.)
Did the grass that killed these cows produce levels of cyanide-based toxins on par with what other poisonous wild plants produce? I.e. are we dealing with a true horror flick here, where a new Big Bad has come to town that we’re gonna need help slaying? And a follow-up question, does any common grass normally produce cyanide, but at such low levels that there’s no impact? (“Dosage matters!”)
What is Tifton 85? How was it made? All plants are capable of cross-breeding and mutating. From reading online, Tifton 85 is a crossbreed (good ol’ fashion breeding, just like Mom and Pop used to make) between “a South African grass and Tifton 68.” I can’t find much about Tifton 68, which has been around since at least 1984, possibly longer. (By the way, Tifton grasses are breed and created by the United States Department of Agriculture research station in Tifton, Georgia; the number refers the to the specific variant; so higher numbers are newer.)
Is there something specific about Tifton 85 or the GM process used to make it that lead to the mutation? I believe a lot of viewers will see the phrase “GM grass” and automatically assume that it’s the “GM” aspects that caused the grass to mutate. But based on the dates for Tifton 68, I’m not even sure that Tifton grass could be GM in the modern sense; i.e. more than just conventional cr0ss-breeding. (Yes, cross-breeding changes the genes. Just like your genes are a combination from your two parents.) If Tifton 85’s lineage consists of only crossbreeding, then I think it’s unfair to call it “GM Grass”, as the common usage of GM has come to mean genetically engineered (“things that could never happen in Nature”). Do you think that this is a fair distinction?
Other questions you want answers to? Anwers and critiques to my notes, of course, also appreciated.
P.S. If you’ve not seen Just Label It, check out http://justlabelit.org/
Awesome Food: UCSC Seed Library
Awesome Food is happy to announce that its fifth micro-grant of $1,000 has been awarded to Andrew Whitman of the UCSC Seed Library, which is a seed repository and lending service based at the University of California at Santa Cruz. Whitman is among nearly 800 applicants from around the world who have applied for grants from Awesome Food, a chapter of the Awesome Foundation, which awarded its first micro-grant in October 2011.