Around 2007, a bar in lower Manhattan became famous for its bacon old-fashioned, a cocktail that made use of a clever trick of chemistry to saturate whiskey with the flavor of Tennessee country bacon.
The bartenders steeped bacon fat in the whiskey, allowing its flavors to migrate to the alcohol. When the fat was strained off, it left behind a beautifully flavored booze. They called the technique fat-washing.
Fat-washing is easy to do at home, and since then many home cocktail-makers have experimented with their own combinations.
How To CocktailHow to Cocktail
What is Fat Washing?
Here’s the science behind the technique: A liquid in which other substances can dissolve is called a solvent. Solvents can be grouped into polar and nonpolar solvents, depending on how their molecules are charged. Water is the classic example of a polar solvent. Oil is a nonpolar solvent.
Polar solvents are able to dissolve polar substances, and nonpolar solvents are able to dissolve nonpolar substances. Most, but not all, of the flavor compounds in the world are nonpolar, which means they dissolve nicely in fatty foods but not in water.
The flavorful smoky, porky compounds in bacon are an example; they’re soluble in fat, and in a strip of bacon they exist dissolved in the fat.
Now, alcohol is an interesting solvent, because an alcohol molecule has a nonpolar part and a polar part. That gives it the ability to dissolve fat-soluble flavor compounds and integrate them into a drink.
Side Benefit: Booze-Infused Fat
Some years ago, I realized that the exact same technique also transfers flavor in the other direction: from the liquor to the fat. In particular, this method is a wonderful way to flavor butter for frostings, or baking, or for anything you use butter for.
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How to Butter-Wash Your Booze (and Booze-Wash Your Butter)
The flavor that plain butter imparts to liquor is on the subtle side. For more adventurous liquors, use bacon fat or try browning the butter first, which produces a wealth of Maillard-reaction fat-soluble flavor, which will happily transfer to a bourbon or rum.
1. Grate 8 ounces of chilled butter and place in 16-ounce jar. (If using melted bacon fat or brown butter, which have a more intense flavor, only use 2-3 ounces.)
2. Add about 7 ounces of liquor of your choice, or enough to cover grated butter.
3. Shake to combine.
4. Cover jar and keep refrigerated for at least 24 hours, swirling contents occasionally. Melted fat will solidify during this time. (Flavor will continue to intensify after 24 hours, but more gradually.)
5. Strain liquor and butter through cheesecloth-lined strainer over bowl, pressing butter with spoon to extract liquid.
6. Scrape butter from cheesecloth into an airtight container, and reserve flavored liquor in sealed jar or bottle.
The butter can now be kept in the refrigerator and used any time you need butter.
Simultaneously, the liquor has been gently infused with butter flavor and can be stored indefinitely, then sipped or used in cocktails.
The technique is simple enough to experiment with at leisure. Here are a few different combinations to get you started.
- Butter-wash rum for a lightly buttery rum and Coke and use the butter in buttercream.
- Make a Godfather with butter-washed Scotch and amaretto and add the butter to chocolate chip cookies. Wash the chips in the spirits too for even more punch. Brown butter will make a more intense version of the drink.
- Mix up a butter-flavored mezcal old-fashioned and spread the butter over radishes.
- To make a bacon fat–washed rye whiskey: Cook the bacon to render out as much fat as possible, and mix that fat in your favorite infusing jar with a spicy rye. Rest, chill, and strain.
Try out different combinations of fats and liquors, and let us know your favorites!