S2: Episode 4: Why Acidity In Coffee Is A Good Thing!
The word ‘acidity’ doesn’t sound particularly pleasing, especially as its so often associated with indigestion. So you might be surprised to discover that in the Specialty Coffee world acidity in coffee is both desirable and prized. In this episode we take a deep dive into acidity in coffee and find that it is about much more than just pH levels. That said, in this week’s FACQ we discover the actual pH of coffee and how it relates to other drinks. Is coffee more acidic than Coca Cola? Listen to find out!
The Academics of Acid in Coffee is a readable article on coffee acidity by Five Senses Coffee in Australia. (https://fivesenses.com.au/blogs/news/academics-acid-coffee/)
Check out Season 1, Episode 1 on brewing water temperature and its influence on the acidity in coffee:
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Email: thecoffeedrinkersguide@gmail.com
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Hello and welcome to The Coffee Drinker’s Guide, a podcast for the coffee curious where I explore and explain the world of specialty coffee to make your daily coffee better and more satisfying.
I’m Angela Holder a coffee roaster and writer on a mission to fight back against bad coffee by giving you the knowledge you need to help you get good coffee and a happier (coffee) life in coffee-break sized episodes. So grab your coffee, pull up a chair and take a break…
This week's episode explores the topic of acidity in coffee - and although the word can bring up bad connotations, you may be surprised to hear that it's actually desirable in specialty coffees...and later I’ll be answering a question about the actual pH of coffee - so stay tuned for that…
One of the most generally misunderstood aspects of coffee is its acidity. It can get confusing as while acidity can refer to the actual measurable acids present in coffee beans (its PH levels), it is also an important aspect of a coffee’s flavour which is perceived by the tongue as a sour sensation. Professional coffee tasters are way more concerned with this perception of a coffee’s acidity than its actual pH. To muddy the waters further, it is the quality of a coffee’s acidity that matters most in specialty coffee and is a fundamental aspect of what defines the very best coffees - so you can see why the concept of a coffee’s acidity is a slippery thing to get to grips with. Nevertheless, since it is an important characteristic of specialty coffee its time to dive into what acidity means in coffee and see how far we get…
When appropriate, I mix up the order of the usual segments - so firstly acidity and the taste
The acidity of a coffee is perceived on the tongue as sourness and is a sharp sensation. This may sound unpleasant but in conjunction with the aroma of the coffee this sour-sharpness is perceived as the highly pleasing fruit flavours of citrus, berries, stone fruit and tropical fruit. These acidic flavours are prized by professional coffee tasters as they balance the other basic tastes of sweetness and bitterness in coffee, contributing to the complexity of its flavour which ultimately makes it more interesting to drink. But it is definitely not the case that high levels of acidity in a coffee are automatically considered to be good and low levels bad. The quality of the perceived acidity is also important. A coffee with a low level of acidity which is complex, nuanced and pleasing is better than one with a piercingly high level of one dimensional acidity. When coffee people talk about coffee flavours we tend to avoid using the word ‘acidity’ as it immediately conjures up thoughts of vinegar and indigestion, so euphemisms like ‘fruity’, ‘bright’, ‘tart’ or ‘lively’ tend to be used instead. Yup, guilty as charged...
Next acidity and the brew
Acidity is an aspect of a coffee’s flavour that can be affected by brewing variables, or in other words, those brewing factors that can change from brew to brew. In particular the acidity of a coffee can be modified by the brew method, grind size, temperature and quality of the brewing water used. This means a certain amount of control over the expression of the acidity of a coffee is in the hands of the person brewing it. One of the easiest ways to influence a coffee’s acidity is with the brewing temperature water. As mentioned way back in season 1, episode 1, which I’ll link to in the shownotes, brewing with water at the higher end of the ideal brewing water temperature range will take the edge off very acidic light roasted coffee, if that is what you want. When a coffee is brewed well, the result is an harmonious coffee with an acidity which is pleasing and balanced. Brewed badly, the acidity may be either muted, making the coffee taste flat, or ramped up to a mouth puckering sourness which will make you regret your life choices. It really is in your hands…
Finally acidity and the bean
All brewed coffee is weakly acidic due to the presence of various acids in the beans. The organic acids in coffee which are also found in fruits are what give coffee its fruity flavour and are the source of the sometimes fanciful coffee descriptions on coffee packets. Acids are both created and destroyed during the roasting process with the final composition of the various acids present in the beans, being determined by the length of the roast. Shorter or light roasts have more acidity than longer or darker roasts. That being said, roasting can only develop what is present in the raw beans and a coffee with intrinsically low acidity is not going to be made more acidic by roasting. The intrinsic acidity of a coffee is dependent upon where the coffee was grown, the botanical variety and how the coffee cherries were processed to produce the raw coffee beans. Coffees with the most pleasing and highest levels of acidity are washed Arabicas grown at high altitudes under partial shade; while low grown coffees are known for their lower levels of acidity. So if you love bright, tart and fruity flavours look for the highest grown washed coffee you can find.
And now its time for a Frequently Asked Coffee Question…
And this episode’s question is…
Just how acidic is a cup of coffee?
OK, so this is the ‘science bit’. Whether a liquid is acidic or alkaline is indicated by its position on the pH scale. This is measured on a scale of 0 -14, where pH0 is highly acidic and pH14 is highly alkaline, while pH7 is neutral. A cup of black coffee is around pH4.5 to pH5.5, so is weakly acidic. The precise pH of a coffee varies depending on the beans in question and how those beans have been treated. You may be interested to know that coffee is less acidic than fruit juice which clocks in at pH2.5 to pH4 and is a lot less acidic than Coca Cola at around pH2.5. Milk is slightly more alkaline than coffee at around pH6.5, so adding milk to coffee makes it a little less acidic. If you want to know more about the acids in coffee I’ll put a link in the show notes to a very readable article about it.
Thank you for listening to this episode of The Coffee Drinker’s Guide and that was all about acidity and coffee. If you were confused about acidity before I hope this cleared it up. Also, are you a fan of bright and fruity acidic coffees or do you avoid them? Send me a text using the link in the show notes and let me know. In the next episode we are digging into something that is even more important when defining the quality of a coffee and that is defective beans - its a fascinating subject so make sure you hit follow to subscribe to the show so that you don’t miss it. If you know someone who also loves coffee please tell them about the show and rate and review this podcast wherever you listen to your podcasts to help other coffee curious people find the show too. If you have a question about coffee or a topic you’d like me to cover please get in touch. I’m on Instagram @thecoffeedrinkersguide or email me at thecoffeedrinkersguide@gmail.com. Thanks to my executive producer Viel Richardson at Lusona Publishing and Media Limited. You can find him at lusonapub.co.uk. Until next time I’m Angela Holder thanks for sharing your coffee break with me - the best way to tackle life is one coffee at a time and here’s to better coffee!
The Coffee Drinker’s Guide is a Blue Sky Coffee Project