Olive oil-washed gin is the savoury end of fat washing. The technique is identical to a coconut or butter wash — combine, rest, freeze, filter — but the flavour it carries across is green, grassy, and faintly peppery, which is a register gin botanicals do not reach on their own. It is the base of the Dirty Gilda, and it is the single easiest way to make a stirred drink feel expensive.
Pick an Oil You Would Eat From a Spoon
This is the whole decision. The wash transfers what is in the oil, so a flat supermarket blend gives you texture and almost no flavour, and a good peppery Picual or Koroneiki gives you the bitter-green bite that makes the drink. Taste the oil first. If it catches at the back of your throat — that scratch is oleocanthal, the same polyphenol that makes fresh oil taste peppery — it will show up in the glass. If it tastes of nothing much, so will the gin.
The Freezing Step Is Fussier Than Coconut
Coconut oil sets hard at fridge temperature. Olive oil does not — it is mostly oleic acid, and it goes cloudy and thick well before it goes solid, which is why a bottle in a cold kitchen turns waxy rather than firm. In a domestic freezer at around -18°C it will set firm enough to filter, but it softens fast on the counter. Keep the jar and the filter in the refrigerator throughout, work in one go, and do not walk away mid-pour. Warm oil goes straight through a coffee filter and you will be doing it twice.
Ratio and Contact Time
A hundred millilitres of oil to three hundred of gin — one part to three — is a heavy wash, and it should be. Gin is not a flavour vacuum; it already has juniper, coriander, citrus peel and root in it, and a timid wash just gets buried. Shake vigorously to break the oil into as many droplets as possible, because contact area is what drives the transfer, then leave it at room temperature until the two layers have fully separated again. A few hours is enough; overnight does no harm.
What It Does in a Drink
Two things, and the texture one is the bigger. Trace lipids left in the gin coat the palate, so a stirred drink built on it lands rounder and finishes longer than the same spec made with untreated gin. The flavour is subtler: a green, olive-y savouriness sitting under the botanicals rather than on top of them. Nobody tastes this blind and says "olive oil". They say the drink feels like it was made by somebody who knew what they were doing.