How to Make Milk Transparent? Is Clarified Milk Latte Delicious?

Clarified milk made a splash at the 2021 World Coffee and Spirits Championship, and while it's clearly a dairy product tailor-made for coffee, it hasn't swept the market the way you might expect — you'll only find it at a handful of coffee shops.

Naturally, FrontStreet Coffee was curious: what would a latte made with it actually taste like? So today we're making a "transparent" latte and finding out.

Milk Clarification Technique

The principle behind clarified milk is using an acid to alter the protein particles in milk. Milk proteins fall into two groups: large amounts of casein and small amounts of whey protein. When casein meets acid, it separates from the whole, forming independent flocculent particles that precipitate out. Filter those off, and you're left with clear, transparent milk. The technique itself is nothing new — it has existed since the late seventeenth century, where it even earned a professional name: "milk washing."

What's the Difference Between Clarified Milk and Regular Milk?

Filtering removes only most of the proteins. In essence, nothing else changes, because the translucent liquid that passes through still contains the whey protein, water-soluble vitamins, lactose, minerals — plus the acid you added.

That added acid, of course, gives the filtered milk a noticeable sour edge. So for this experiment, we sweetened one portion of the transparent milk with 30g of white sugar to neutralize the acidity, and compared the results.

How to "Wash" Milk

Good question! First, pour it into a washing machine... and then...

Just kidding! Start with any acidic fruit — lemon, orange, pineapple, grapes — and juice it.

Then heat the milk. Warm milk encourages the proteins to form flocculent precipitates more readily.

Mix milk and lemon juice at a 10:1 ratio (in this experiment, 200ml milk and 20ml lemon juice), pour the mixture into a prepared container, and refrigerate it for 10 minutes so the casein fully separates.

Filter out the curdled protein — it looks a bit like tofu pudding — through filter paper.

Looks like even the neighbor wants in on it. The whole process takes about 20 minutes and yields roughly 150ml of transparent milk.

Production complete~

Tasting Time

First, the clarified milk on its own: a faint milky scent, an overall sour taste — as expected, given the acid — and a body only slightly thicker than water.

Next, the transparent latte with straight espresso added: sharply acidic, almost like a sour Americano.

Finally, the transparent latte with the sugared batch: with the sugar balancing the acid, sweetness and sourness settle into equilibrium, and the result tastes like coffee with a lemon-tea character.

The verdict: clarified milk doesn't work well straight from the glass or mixed directly with espresso. It needs the right formulation to become a genuinely appealing specialty drink. (It may also be that lemon was a poor choice — try other fruits and see.)

Finally, here's a very satisfying espresso moment~

PS: This high-concept latte will not be available at FrontStreet Coffee stores

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FrontStreet Coffee

FrontStreet Coffee Recommendation

If the transparent latte taught us anything, it's that milk drinks live or die on the beans underneath. Here's how to pick beans for milk coffee:

FrontStreet Signature Blend — Our longest-running house espresso blend, built on Brazil Cerrado and Colombia Huila. With Brazil leading the profile, a latte made from it shows layered nut flavors — almond, walnut, Marcona almond — silky and lingering on the palate. A perfect milk companion.

FrontStreet Classic Blend — If you want a latte with abundant crema, choose this: a touch of Robusta in the blend delivers extra golden foam and instantly amplifies the body and caramel aroma. Mellow, warm, and easy for anyone to enjoy.

FrontStreet Strawberry Candy Blend — A fruit-forward espresso blend that recreates a vivid strawberry-gummy sweetness from the native flavors of different Arabica origins. Ideal for drinkers who avoid bitterness and for shops wanting a distinctive signature milk drink — one bag covers pour-over, espresso, and everything in between.