Lab: Salmon Gravlax

Salmon Gravlax

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.

In a bowl, mix together:
     5 teaspoons (30g) kosher salt
     1 tablespoon (12g) sugar
     3 tablespoons (12g) finely chopped fresh dill
     1 teaspoon (5 mL) vodka
     1 teaspoon (2g) crushed peppercorns (ideally, use a mortar and pestle)
On a large piece of plastic wrap, place:
     1 pound (450g) salmon, washed and bones removed; preferably a center cut so that its shape is rectangular
Sprinkle the salt mixture over the fish and massage it in. Wrap the fish in plastic and store it in the fridge, flipping and massaging it twice a day for a day or two.
Store it in the fridge and consume within a week.
Remove the skin from your salmon fillet.
Remove the skin by placing the fish skin-side-down on a cutting board and carefully running a knife along the surface between the skin and flesh while using your hand to keep the fish from sliding around.
     • Vodka is used here as a solvent to dissolve some of the non-water-soluble aromatic compounds. You can substitute other spirits, such as cognac or whiskey, to bring additional flavors in. And in place of dill, try using coriander seed, loose tea leaves (e.g., Earl Grey or Lapsang Souchong), shallots, or lemon zest. The Scandinavians traditionally serve salmon gravlax on top of bread with a mustard dill sauce.
      • You can substitute other fatty fish, such as tuna, for the salmon and obtain a similar texture.
     • This recipe is a bit heavy on the salt—6% by weight—to err on the side of safety. You can reduce the saltiness before eating the fish by rinsing the finished product in fresh water. Curing above 3.5% salt prevents most common bacterial growth, but not all. Modest concentrations of salt prevent Gram-negative bacteria—which are the most common ones found in food—from growing, but won’t handle the few that are Gram-positive, such as Listeria.
     • Salt curing—as is done in salmon gravlax— is the first step in making lox. After curing, lox is also cold-smoked, which is the process of exposing a food to smoke vapors that have been cooled down. You can approximate the flavor of lox by adding liquid smoke to the rub.

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.

Pumpkin Soup

Soups don’t have to be complicated, as this simple pumpkin soup shows. This was originally a butternut squash soup recipe in Cooking for Geeks, but like any good geek—that’d be anyone who’s curious how things works and is willing to play with things—I thought, “Hey, pumpkin is a gourd, too; so that should work!” Sure enough, it does. And with hundreds of millions of pumpkins showing up on doorsteps across our nation today (November 1st), it’s also a great way to reuse, reduce, and recycle!

Purée in a food processor or with an immersion blender:
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Tim O’Reilly’s Jam and Scones

Tim shows his method for drying apple rings in the hot California sun.

Re-blogged from… -J

For his recently released book, Cooking for Geeks, author Jeff Potter interviewed prominent researchers, food scientists, knife experts, chefs, writers, and more, including author Harold McGee, TV personality Adam Savage, and chemist Hervé This. Some provided recipes, others offered tips and tricks, and each brought his or her own geeky insights into the space where science and cooking meet. In one case, the contribution was a comic (by Randall Munroe of xkcd). As you can imagine, while preparing the book, Jeff had access to a geek whose name is eponymous with the company that published his book. The excerpt from Cooking for Geeks that follows includes part of their conversation, along with the recipe for Tim’s now-famous homemade scones.

Jeff: You say you don’t consider yourself a foodie at all?

Tim: No. In fact, I kind of make a small number of things that I make repetitively. A lot of what I do is driven by the fact that I hate to waste things. So hence jam because there’s all this great fruit. [Tim has numerous fruit trees.] Right now I’m doing dried apples. But let me put these scones in. [Tim had been making scones as we started.] This is something that I figured out a long time ago. I make this big batch and it’s too much for two people so I made a batch and then I was like, oh wait, I can just freeze it.

Jeff: How did the thought of freezing it come to you?

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NPR’s Science Friday & Cooking for Geeks

Jeff Potter, author of Cooking for Geeks, with Ira Flatow, host of NPR's Science Friday

I had the privilege of being on NPR’s Science Friday last Friday. In a word, it was amazing. If you haven’t listened to the podcast yet, click here to listen to an MP3 of me on NPR (file size: 16 MB; runtime: 35 minutes).

Things that happened to me as a result of being on NPR:

1. I heard from people I hadn’t thought of in years. High school teachers of mine. Friends of my ex. Even a childhood friend who lived a few doors down from me when growing up, whom I’ve not thought about for 15 years. Her dad had heard the NPR story and passed it along. Amazing.

2. My book went to #1 in Amazon’s Food, Cooking and Wine section, and up to #37 in books. That’s #37 across all books. Amazing. I am honored and deeply humbled to have been the #1 top-selling cookbook in America, even if for only a weekend.

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Duck Confit Sugo

I had my first bite of duck confit in France before I was even a teenager, and fell in love with it immediately. Duck confit tastes entirely different than duck cooked almost any other way; it’s like comparing bacon to pork: same animal, different reality.

Of course, at the time I wasn’t paying attention to the word “confit”, and upon returning to the US, ordered “duck $whatever” ever single time I ate out. It never worked. I’m sure I ate some amazing duck, but at the time, duck confit just wasn’t cooked in the US.
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Seared Tuna on Wonton Crackers with Wasabi Avocado Mousse

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This is a guest post by Clarissa Monét, who made this for me last week. Thanks, Clarissa! -J

This recipe is super simple, yet über comforting and satisfying. Fresh ingredients and a knack for what tastes good are all one needs to make this appetizer delicious!

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Grilled Chicken with Greek and Japanese Marinades

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I’ve been teaching a friend of mine how to cook and one of the first things to come up is the question of flavors and tastes—how do I know what ingredients will taste good together?

One place to start is by looking at ingredients that are commonly used together. There are two easy places to see this: one is in the ingredient list on sauces and marinades—if the pasta sauce has tomatoes, oregano, mushrooms, and onions, then an omelet with those things will probably taste good too—and the second place is to look at cultural traditions.

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