Oil in drinks

Monica Berg outlines why fat washing is a favourite method of adding indulgence, richness and softness to a drink.

Of all the techniques I love, one of the closest to my heart is what you would call ‘fat washing’ – which is essentially utilising fat’s excellent ability to carry flavour. Much like alcohol, it has the ability to lock in flavour – and transport it – but unlike alcohol at times, it preserves the more volatile and delicate nuances that we’re often trying to express in our drinks.  

Historically, fat has always been recognised for its ability to ‘absorb’ flavour or fragrant compounds. Whether it’s by making flavoured oils for the kitchen such as chilli or herb or frying chips in duck fat – or enfleurage, a process invented in South of France, which is traditionally used by the perfume industry to extract fragrant compounds from delicate flowers such as jasmine and tuberose.  

There are many reasons we choose to use fat washing as a technique, some more obvious than others, so let me get right into it. 

Adding flavour  

This might sound boringly obvious, but I’ve always been fascinated by oils – olive oil, various kinds of nut oils such as hazelnut, walnut or coconut – because they all add their own distinctive flavour to the spirits you infuse them with. I’m sure I’m not the only bartender who, when tasting a really high-quality virgin olive oil, thought: “Wow, that’s amazing – how can I make that into a drink?”  

Of course, the answer is that you can – it just requires a bit of work. Because you only really want the flavour of the oil, not necessarily the oil itself, which means you need to add a few more steps to your prep. In short, it goes like this: mix chosen oil and spirit, let infuse for desired time, place in freezer overnight, strain through paper (coffee) filter until spirit is (again) clear. It will now more or less look the same, but once you taste it, it will be completely transformed. If you started with olive oil and gin, you will now have a gin that tastes also of the oil it was infused with – but with none of the fat and heaviness.  

There are, of course, more ways of adding flavour using oils – the most common, perhaps, to
use the oil itself to carry the desired flavour, be it herbs, spices, chilli or other aromatic ingredients. It adds an extra step to your prep – infusing the oil first – but the rest goes pretty much the same
as above. Any time you work with fragile ingredients, such as flowers or some herbs, I find it
super effective. 

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Adding texture  

This is perhaps one of my favourite ‘manipulations’. Personally, I’ve only ever managed to do this with fats that are solid at room temperature – butter, duck fat, beef drippings etc. They also add flavour, but the main reason I love these processes is that they so magically seem to ‘wrap’ the spirit in a veil of indulgence, richness and softness. It’s almost like they neutralise the sharp edges to leave a rounded, mellow and moreish version of the spirit you started with. My personal favourite is butter – because let’s be honest, the only thing better than butter is more butter. And for me, I always turn to cultured butter. It also conveniently leads me to my last point. 

Adding acidity 

When using cultured butter, it’s almost like the perfect hat trick: you get the rich creamy flavours; the decadent and soft texture; and last, but not least, the tangy finish from the lactic acid. For a Martini for example, in my humble opinion, it is the perfect evolution – and not far away from the perfect drink. 

Actually, that wasn’t my last point. Because there is one more way we use fat quite often, and that is to tame heat. With that I mean, for example, when you want to showcase the flavour profile of a quite hot chilli like aji amarillo or habanero – but without all the heat. Aji amarillo is a wonderful Peruvian chilli that is super fruity with mango and passion fruit notes, but it’s also quite hot, registering 30,000-50,000 on the Scoville scale. By first infusing it in the oil, and then fat-washing the spirit, you keep all the fruity notes, while controlling the heat – and it allows you to showcase the different sides to the fruit but not burn your palate. And trust me, it does burn. 

I’m sure there are endless more ways to use fat in drinks, and we certainly discover new flavours and ingredients every month – lately we’ve been playing around with coffee oils a bit – so all I can say is that I think the future is, if nothing else, flavourful.