A Journey Through coffee… Part 2 “Some Like it Hot” (by Jon)

In my last blog, I discussed my preference for drinking black filter coffee at near body temperature, as the fruity acidity, sweetness, and many other flavours really shine through. This got me wanting to talk about a much-discussed topic in any place that serves coffee. As long as I’ve been serving coffee, some customers have been sending coffee back as it’s not hot enough. It is often referred to as “cold” and sent back for reheating or remaking. 

As a topic, it is a delicate situation in which baristas and customers often differ in opinion, so I wanted to share some of my insights and research as a way of bringing coffee makers and drinkers closer together. 

The temperature at which drinks are served is as much about culture as it is personal preference and science. Nothing’s set in stone.

For example, people in North America tend to prefer ice-cold water at mealtimes, whereas Europeans are usually happy with it just below room temperature. In Asian countries, meanwhile, you’ll often find people drinking hot water or tea with their food. Also, some people prefer coffee that is extra hot. 

There is some science to the influence of the temperature of drinks (and food) and how they taste. Understanding this science may be useful.

Humans are really bad at tasting things that are too hot or too cold. The reason for this is that the taste buds in your mouth have tiny microscopic channels that send signals to your brain allowing you to taste sweet, sour, bitter, umami and salt. 

If the liquid is too hot, then the tongue protects itself by closing these microscopic channels which in turn stops the flavour signals reaching your brain. This nicely explains why if you make a bolognaise and taste it when it’s simmering it just tastes hot. The closed taste channels stop you from picking up any flavours at all.

The same applies to coffee. When served hot (80 °C or over), the tongue’s protection mechanism will stop you from experiencing anything other than heat. As the coffee cools, those channels on your tongue start to open up again, allowing you to enjoy the range of flavours that come with a quality coffee and let’s face it, good quality coffee costs more, so why hide the quality behind temperature? 

The same effect also applies to bitterness. There’s a lot of poor quality, cheap, bitter coffee served across Devon ( like you, I still taste some shockers). It’s no surprise that anyone who’s had many poor coffees in the past prefer it hot as the heat will also hide unpleasant bitterness. 

This may also provide some insight as to why some people always want milk with their Americano, as the sweetness of the milk will help mask the bitterness of poor quality coffee.

So what about the temperature of Lattes or cappuccinos? Well, there’s some science here, too. 

The source of sweetness in milk is lactose. When milk is heated for a latte, then this lactose is converted to glucose and galactose. These two molecules are much sweeter than lactose which is why milk gets sweeter when it’s heated. This is however up to a point. Beyond 65C then lactose decomposes and sweetness is lost.

The reason why milk and coffee go well together is that the sweetness of milk complements the strong, bold and in the case of some coffee, bitter notes. 

Lose the sweetness of milk, and the balance of flavours is lost, often resulting in a bitter brew. 

At the vineyard, everyone who makes coffee and steams milk uses a thermometer to ensure the milk stays in this sweet, tasty zone, and anyone who’s served our filter coffee is encouraged to experience the different flavours as it cools. (Well, I’ll enthuse about this anyway) . We also use a high-quality coffee that is lightly roasted to ensure the inherent range of quality flavours is still present and not masked by the taste of roasting.

 Next time you come for coffee at the vineyard, if you’re minded to ask for your usual extra hot cappuccino or latte, perhaps try taking it as it comes and drink it with flavours in mind as opposed to habit. Or perhaps be mindful of the cooling effect on your drink. 

As I said at the beginning, however, it’s your drink and your experience, and as long as you’re happy then we’re happy, so if you're one of the “some that like it hot” then we’re happy to oblige.