So I was asked by Mark to write about coffee. At first I was overjoyed at the thought. This was, after all, what I had wanted to do for ages. So I got sucked in; I put my head down and I wrote. I put together a little over 1500 words and I reread it. It was gibberish, strewn with jargon and technical talk, laden with scientific references. It was too much, but then where does one start with coffee? Well, at the beginning of course, the beginning being the flavour of coffee and in this article I am going to focus on how temperature affects flavour.
Customer: “My coffee is cold”
This is something one hears all too often, and you begin to think as a consumer these baristas really ought to know how to steam milk to the right temperature – heck it’s their profession! What you’ve just done is stumbled into a great coffee shop, riding the 3rd wave of coffee – you’ve just had a cup made by a coffee specialist and know that there is method to this madness.
The first point to consider is how your tongue works. Simply put, it registers flavours better in a certain temperature range. If we use ice cream as an example; One does not taste the sweetness when it is frozen, only once it melts on your tongue (Go get an ice cream, I’ll prove it). Similarly, melted ice cream can be hard to drink because of its intense sweetness.
Beverage producers in the modern era focus less on quality and flavour and more on ensuring the beverage is served at a certain temperature. I call this the “warm beer phenomenon”. In my home country there is a very popular malt beverage and the company advertises its flagship bottle being drunk in frigid conditions. The merchandising team stocks bars with powerful sub-zero fridges and the design team has even put a large snowflake on the label that turns blue when it is cold enough to drink. They are planting the seed that this has to be served extra cold.
Ok, so what does this have to do with coffee? The answer is as follows: the colder the beverage the less you are actually tasting (your tongue works best tasting things between 15-50 degrees). Once the beer in question warms slightly you will more than likely throw it out.
Larger coffee chains use this technique too. Their hot drinks are scalded and their cold drinks are over iced – you will even see crushed ice being used instead of blocks. This crushed ice has an increased surface area in contact with the liquid so you have significant, rapid cooling.
What it boils down to is this: These coffee outlets are hiding their flavour, likely because it is bad. They are serving super cheap beans on subpar machines with undertrained baristas, but you the consumer are left unaware as you cannot taste much and that’s exactly what they want. The consistency is also much greater, they are consistently bad.
The second reason certain shops serve warm coffee is this: Heating milk to and not above a certain temperature enhances the inherent sweetness. Above 65 degrees you start to breakdown the lactose present in the milk (lactose can be thought of as milk-sugar). This as well as other reactions occur at higher temperature and affect not only sweetness, but also texture. Overheat your drink and you are left with milk that has terrible texture and much lower levels of sweetness.
But what if my coffee is served without milk, it’s still not hot enough?! Well, the same applies with regards to tasting only between a certain temperature range. However, if actual ground coffee is subjected to temperatures above 93 degrees, you start burning the coffee and this inevitably results in a bitter, over extracted drink. This is similar to what happens when one steeps their tea for too long.
So before sending your warm coffee back next time (and you may, you are entitled to whatever temperature you wish – you are paying for this drink), take a sip, think about what you’re tasting and know that you will sacrifice this fantastic orchestra of flavours, aromas and textures when overheating your coffee.
Post by Grant Mouton
Self–proclaimed coffee guru, coffee education addict, SCAA/SCAE accredited. Brand manager at % Arabica.