Fat Washing Spirits: Infusing Flavor Through Rendered Fat

Fat washing sounds complicated but it's a straightforward technique that infuses spirits with flavors from rendered fats like bacon grease, brown butter, or olive oil. The fat carries flavor compounds into the spirit, then you remove the fat, leaving enhanced spirit without greasiness.

The process works because alcohol is a solvent that extracts flavor compounds from fat. When you combine warm rendered fat with room-temperature spirit, flavor molecules transfer from the fat into the alcohol. After the fat solidifies in the freezer, you remove it, taking only the flavor and leaving the actual fat behind.

Here's the standard method for bacon fat: render bacon and save the grease. For every 750ml of spirit, use approximately 1.5 to 2 ounces of rendered bacon fat. Combine the warm (not hot) fat with room-temperature bourbon or rye, stir gently, and let it sit at room temperature for 4-6 hours. The mixture will look cloudy as fat disperses throughout the liquid. Transfer to the freezer for at least 6 hours or overnight. The fat will solidify on top in a solid layer. Remove the container, scoop out the solidified fat with a spoon, then strain the spirit through cheesecloth or coffee filters to remove remaining fat particles.

Brown butter follows a similar process but requires cooking butter until the milk solids caramelize and turn golden brown. Let the brown butter cool to warm (not hot), then combine with rum or whiskey using the same ratio—about 1.5 to 2 ounces of brown butter per 750ml of spirit. The process is identical: mix, let sit at room temperature for 4-6 hours, freeze overnight, remove solidified butter, and strain. Brown butter-washed rum adds nutty, toasted complexity that works beautifully in tiki drinks or rum Old Fashioneds.

Olive oil is different because it doesn't fully solidify in the freezer like animal fats do. Use high-quality extra virgin olive oil for maximum flavor—about 1 ounce per 750ml of spirit. Combine room-temperature oil with gin or vodka, shake well, and refrigerate (not freeze) for 12-24 hours. The oil will separate and float on top but won't solidify completely. Carefully decant the spirit from underneath the oil layer, then strain multiple times through cheesecloth to remove oil residue. Olive oil-washed gin creates savory, peppery notes that work in Martinis or Mediterranean-inspired cocktails.

The key difference is temperature management. Animal fats (bacon, butter) need to be warm when mixed but will solidify when frozen, making removal easy. Oils stay liquid at cold temperatures, so you're relying on separation and careful straining rather than scooping out a solid mass.

This technique requires planning since it takes 12+ hours from start to finish. It's not something you do during service—it's prep work that creates unique house ingredients. The resulting spirit stays shelf-stable and lasts as long as regular spirits.

Fat washing expands your cocktail possibilities beyond what's commercially available. You can't buy bacon bourbon, brown butter rum, or olive oil gin, but you can make them yourself using this technique and create signature drinks that stand out.