Often in conversations about coffee, someone will comment that “oh the coffee was really acidy,” and what they’re talking about is the bitterness of a cup of coffee that perhaps wasn’t fresh, had been poorly prepared, or is just the run of the mill swill that tries to pass for coffee in the majority of places outside of specialty coffee shops.
But acidity in the coffee world is actually a good thing. Recently, Perfect Daily Grind (link here.) published a terrific article about acidity in coffee, and explained the differences, and how to differentiate when you’re tasting coffee:
Coffee Science: What’s Acidity?
“Mm, cranberries, with a distinctly orangey acidity… mm… and red wine,” said the barista to my right, furiously jotting this down on his little notebook.
“Oh yeah, definitely a bright orange, but maybe more like tangerine?” the other barista to my left chimed in.
“Oh yeah, tangerine, definitely orangey,” I nervously added, desperate to seem as avid a coffee geek as everyone else at the table.
But really, all I was thinking was: “What the hell are these people on?! This just tastes like slightly sour coffee! What am I missing here?”
That was my first cupping session, 7 years ago. I, like many others (be honest, now!) had the hardest time deciphering “flavour profiles” and “flavour wheels”. It all tasted like, well, coffee to me. Sure, some were more sour than others and some more bitter than others, but they were still coffee.
Eventually, I figured it would be easier to just remember the names of the different varieties of coffees, and then memorise the associating flavour profiles. And that is how I managed to scrape by as a mediocre barista for the next couple of years, bluffing my way through cupping session after cupping session, “really knowing what I was talking about” – even though I literally had no idea what I was slurping from my spoon.
I eventually grew frustrated by this façade and decided that I wanted to actually learn something at a cupping session. (Hello, that’s why I was going, wasn’t it?) I wanted to be able to get as genuinely excited about tastes as everyone else around me. I wanted to have my own opinions, instead of parroting everyone else’s.
Acid is a naturally occurring product in tonnes of foods, like lemons, vinegar, yoghurt, and even coffee. There are literally hundreds of different acidic compounds in coffee alone, ranging from the familiar (like citric acid) to the huh-wha-what?? (like 4-monocaffeoylquinic acid). But for the purpose of this article, I’m going to only talk about the primary acids that affect taste.
- Citric Acid
Citric acid, like its name suggests, exists in high concentrations in citrus fruits. In fact, it can make up almost as much as 8% of the dry weight of these foods. It’s undoubtedly the most commonly occurring acid in all fruits and vegetables, as well as the easiest to identify.
- Malic Acid
Malic acid has a flavour that is most often associated with green apples (after all, it was derived from the Latin word “malum”, meaning “apple”). You’ll find malic acid in its purest form in rhubarb, in which it makes up the primary flavour.
In the culinary world, malic acid is commonly associated with limes, but it’s much easier to think of it as “unripe fruit flavour”. The acid generally decreases in concentration with increasing fruit ripeness, so anything green like green grapes, kiwis, or gooseberries would be on the cards.
Loads more info here: Coffee Science: What’s Acidity? – Perfect Daily Grind
The article continues with more types of acidity & how best to refine your palate by just paying attention as you eat your favorite fruits and vegetables. A must read…