Coffee with milk is one of the most popular ways to drink coffee anywhere in the world. Cappuccino, latte, flat white: each has its own ratio of milk to espresso, and that ratio drives the flavour. But have you ever stopped to think about what the strength and the extraction of the shot underneath are doing to the finished drink?
How espresso strength changes a latte or a cappuccino
Strength, meaning the concentration of dissolved solids in the shot, is one of the things that decides how a milk-based coffee tastes. A strong shot, say 10-12%, carries more dissolved coffee and can taste more intense. At small volumes, though, it can lose its balance, and you notice that as soon as the milk goes in.
Take a cappuccino. Pull a short, intense shot under it and you get a powerful drink, but not necessarily a harmonious one. A longer shot, lower in strength, tends to sit better in the milk and gives you a more balanced cup.
Extraction and the quality of the shot
Extraction is how much of the ground coffee ends up dissolved in the cup. The figure usually given as optimal is 18-22%, the window in which you pull out the best aromatics and flavour without the bitter or sour notes that sit on either side of it.
For milk drinks, the shot has to be balanced. A short shot, ristretto style, is more concentrated but may not carry the full range of flavours. A longer shot delivers more dissolved solids, which means a richer taste once it meets the milk.
An experiment: how much does the taste change?
Working with cappuccinos, we compared two shots:
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Ristretto: 18 g of coffee to 32 g in the cup. Strength came out at 10.8%, which gave an intense taste but put fewer dissolved solids into the finished drink.
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A longer shot: 18 g of coffee to 40 g in the cup, strength 9.2%. More dissolved solids, and a richer, better integrated flavour profile.
The conclusion: the ristretto was more concentrated, but the longer shot worked better with the milk and produced a drink with more balance and more flavour to it.
What the milk is doing
Milk works as a natural buffer. It softens the acidity and bitterness of espresso and brings its own sweetness and creaminess. That makes the quality of the milk, and the ratio of milk to espresso, decisive. A lower-strength shot can let the subtler notes of the coffee through instead of burying them.
How to match espresso to milk drinks
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Start with the beans: go for specialty coffees with a flavour profile worth hearing.
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Play with the ratios: try different amounts of espresso against milk until the combination clicks.
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Check your strength: a longer shot often gives a more harmonious result in milk.
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Mind the milk: fresh, higher-fat milk, or a plant-based alternative, is what gives you the texture.
Finding the balance
Strength and extraction have an enormous say in how a milk drink tastes. A longer shot may look weaker on paper, yet it usually works better with milk and gives you a balanced, full-flavoured drink. The trick is finding your ratios and not cutting corners on the beans or the milk. Try different approaches and see which one suits you.
