Water is the hidden ingredient in coffee and milk is the great partner to complement it. I must admit I am a bit of a purist when it comes to coffee.

But if you are one of the millions of people who love milky drinks above all other types of coffee, the quality of the milk and the way it is treated, are extremely important.

With many of these drinks, there are about two to three times as much milk as there is coffee. So if you add milk there are four main questions about milk:

Full-cream or Low Fat milk?

Don’t be too hard on yourself and allow those calories in the milk, it is much more rewarding. It is the butterfat in milk that turns, when heated, from solid fat molecules to a liquid, oily state that enhances the richness of the drink.

When foamed for cappuccino, the higher fat content allows foam to remain silky and moist compared to the drier foam created by low-fat milk.

By the way, the difference between cappuccino with full cream milk and low-fat milk is about 12 calories. So you’d have to drink a lot of cappuccino before the extra calories will have an impact on your waistline.

Why does the Barista insist on serving my cappuccino warm and not scalding hot?

The answer is about the natural sugars in milk, of which the main one is lactose. This type of sugar becomes more soluble as it’s heated, and this is why warm milk tastes sweeter than cold.

If it’s heated too far, however, the milk will scald and becomes less sweet. And it may make coffee taste bitter. Your barista knows what he or she is doing.

Why do some cartons of milk steam well and others don’t?

The important component in milk when steaming is the casein protein content. This makes around 80 per cent of the milk by weight. If the milk is not fresh,

these proteins are degraded by amino acids that form in the milk over a few days. Refrigeration slows this down, but leaving milk out of the fridge for too long can speed up its staling – even though it may still smell and taste fresh. Do not break the cold chain.

A good coffee shop will always use the freshest milk. If you make milky coffee drinks at home, make sure you follow their example.

Don’t buy the bigger milk containers – unless you live with a horde of coffee drinkers and have to make a dozen cappuccinos and flat whites a day.

What if I’m trying to avoid dairy products?

For a variety of reasons some people prefer to avoid dairy products. For these coffee drinkers, other milks are becoming very popular – most notably soy and (more recently) almond.

If protein levels are good in these milks, they can produce adequately foam for cappuccino etc.

The flavor of both is less pleasant in quality coffee compared to the more neutral flavor of ‘regular’ milk. But if you feel you have a compelling  reason to avoid lactose, and are not ready to make the switch to filter or drip-brewed coffee drunk without milk, they’re a reasonable option.

And for those who swear by a good coffee creamer such as ‘It is not inside, it’s on top’, you have good reason to believe it improves palatability and even improves the coffee’s appearance!

Maybe debatable for those coffee purists.