Fat-Washing Bourbon: How to Put Bacon or Brown Butter in a Clear Drink

A bourbon can taste of browned butter, bacon, or toasted sesame and still pour clear as glass, with no slick on top and no cloud in the bottle. That trick has a plain name behind the bar. Fat-washing. It sounds like something that needs special gear, but it is mostly a jar and a wait, so how do you fat-wash bourbon and still end up with a clear bottle?

Flavor in, fat out

The name says you wash the spirit with fat, which sounds backwards the first time you hear it.

Fat-washing infuses a spirit with fat-soluble flavor, then chills it so the solidified fat can be removed.¹

The first half leans on something fat does that water cannot, since a lot of what we call flavor never dissolves in water at all and is oil-soluble instead, which is why a spoonful of fat pulls more aroma out of an ingredient than water ever will.

Fat dissolves and carries fat-soluble aroma compounds, spreading flavor across the palate.²

While the fat sits in the bourbon it slowly hands off its aroma compounds, and the alcohol is happy to take them, so a few hours is enough for the exchange. The second half is a temperature trick, and which fat you reached for is what decides how it goes.

Saturated fats pack tightly and stay solid at room temperature, while unsaturated fats tend to stay liquid.³

A fat high in saturated fat, like butter or bacon drippings, firms into a solid cap in the freezer that lifts off in one piece, while a more unsaturated oil stays looser and takes a finer strain to clear. Either way the aroma has already moved across.

Fat-wash a bourbon at home

You need a jar, a freezer, and a night of patience. The ratios are forgiving enough that being a little off does no harm, and taste has the last word anyway.

• Pick a fat with flavor to spare: browned butter, rendered bacon fat, toasted sesame oil, or coconut oil.
• Melt the fat if it is solid, then stir it into the bourbon at roughly one tablespoon of fat per cup of spirit. There is no need to fuss over the measure.
• Let the jar sit at room temperature for a few hours so the fat-soluble aromas move into the bourbon.
• Freeze the jar overnight until the fat sets into a firm layer on top.
• Lift or skim off the solid fat, then pour the spirit through a coffee filter to catch the last flecks. If it does not come clear the first time, filter it again.
• Taste it: the bourbon should carry the fat's flavor while pouring clear, ready to build into a drink.