Fat Washing Spirits

Fat washing is a bartending technique where a liquid fat is combined with a spirit, allowed to infuse, then frozen and separated. Because fats are soluble in alcohol at room temperature but solidify when cold, the flavour compounds carried by the fat transfer into the spirit — and then the fat can be cleanly removed by freezing and filtering.

The result is a spirit that carries the aroma and taste of the fat (smokiness from bacon, nuttiness from sesame or peanut butter, richness from brown butter) without any greasy mouthfeel or cloudiness.

Bacon bourbon is the most famous fat-washed spirit, popularised by Don Lee at PDT in New York. The smokiness of rendered bacon fat rounds out the vanilla and caramel notes of bourbon beautifully. It is the base for the famous Benton's Old Fashioned.

Other combinations that work well: sesame oil in whisky or rum (nutty, toasted), brown butter in rum (rich, caramel), coconut oil in vodka (clean tropical note), peanut butter in bourbon (works surprisingly well in tiki-style drinks), foie gras in Sauternes or brandy (rich and savoury), olive oil in gin (herbal and round).

You will need: the spirit of choice, the fat, a wide-mouth jar, a fine strainer and cheesecloth, and space in your freezer.

1. Render or melt the fat. For bacon, cook the strips until crispy and collect the rendered fat while warm. For oils, use them at room temperature. 2. Combine fat and spirit in a ratio of roughly 30–60 ml of fat per 750 ml of spirit. More fat = more flavour intensity. 3. Stir or shake to combine. The mixture will look cloudy or milky. 4. Let infuse at room temperature for 4–8 hours. For delicate fats (brown butter, olive oil), 1–2 hours is usually sufficient. Taste periodically — infusion is fast. 5. Freeze overnight or for at least 6 hours. The fat will solidify into a cap on the surface. 6. Break the fat cap and pour the spirit through a fine strainer lined with cheesecloth or a coffee filter. Discard the solidified fat. 7. Taste. If any fat haze remains, repeat the freeze-filter step once more.

The finished spirit should be completely clear and carry the flavour of the fat cleanly.

If the spirit is still hazy after two freeze-filter cycles, try passing it through a paper coffee filter at cold temperature — this removes the last emulsified droplets.

Salt-cured or smoked fats (bacon, duck fat) deliver more flavour than plain rendered fats because curing and smoking add aromatic compounds of their own. The Maillard reaction matters: brown the butter properly, toast the sesame seeds, cook the bacon until rendered and caramelised.

High-proof spirits (above 50% ABV) extract fat flavours more aggressively — be conservative with infusion time. Vodka and white rum show the fat flavour most nakedly; whisky, bourbon and añejo tequila add their own complexity on top.