Maybe I set the bar too high in my own mind, maybe I wasn’t sufficiently clear and maybe (the most likely explanation) it just wasn’t that good of an idea to start with.
UPDATE: Twitter has informed me that the problem is my expectations, and that I should stop being churlish for what many would consider a good result. I have since reviewed my expectations for this – there’ll definitely be a part two… My expectations are likely skewed by the last two times I requested reader participation which each generated 500+ responses.
The idea behind the collaborative learning project was that if you gave a little you got something more in return. The first post on acidity has had 10k+ views, excluding the several thousand who subscribe to the RSS feed. I had hoped that even 1 in 100 page views might yield a submitted link, but for all the views and the thousand of people who read the post I’ve received (to date) 29 viable links on the subject of acidity. (Less than 1 per 400 views)
Let me be clear: I’m not really blaming anyone else but me for this, and I’m not really moaning about it either. This isn’t an “oh poor me!” blog post, I promise you. My predictions of how this would go were based more on my own hopes, rather than evidence or historical precedents.
I’m not yet sure if I am going to continue with the project, or certainly continue it in its current form. I will definitely update the existing blog post with the links submitted on acidity so far, but as for starting a new topic – I don’t think so. Failure is fine, it should be accepted, and sometimes it is ok to let things go and to move on to other projects. There are a few other ideas in the pipeline, so hopefully they’ll come to fruition soon!
This is the first topic in the learning project series of posts. Please click through at the end to share a link for further reading on the topic.
Acidity is an important part of coffee, and weaves its way through the entire supply chain of the industry from variety to picking, from process to roasting and from brewing to tasting. I want to start with the basics, cover some of the tasting aspect and then look at acids specific to coffee.
We tend to define acids as having a pH lower than 7, or as having a sour taste, but these aren’t particularly scientific. In fact there are three different scientific definitions of an acid: The Arrhenius definition, the Brønsted-Lowry definition and the Lewis definition. I think the Arrhenius definition is going to serve us best here which is:
An Arrhenius acid is a substance that dissociates in water to form hydrogen ions (H+) that is, an acid increases the concentration of H+ ions in an aqueous solution.
The important part to note here is the presence of H+ ions, as we’ll discuss this later. It should be noted that his definition specifies an aqueous solution, so you could argue that pure hydrochloric acid, or pure sulphuric acid wouldn’t count as acid but this would be nitpicking.
The measurement of the level of acidity is done through measuring the number of these H+ ions, and is usually communicated through the pH scale. While there is some disagreement on exactly what pH stands for but the Carlsberg Foundation (tied to the Carlsberg Labratory where Søren Peder Lauritz Sørensen did the work to first introduce the scale) claims it stands for “power of hydrogen”.
It is important to remember that the pH scale is logarithmic. This means that each whole value below 7 is ten times more acidic. Thus a pH of 4 is 10 times more acidic than a pH of 5, and 100 times more acidic than a pH of 6.
Acidity is often described as being one of the 5 tastes, which is deeply unfair to other tastes such as pungency, astringency, piquancy or metallic tastes. (Much like saying we only have five senses ignores senses like balance or the sensation radiant heat). It is a critical part of the foods we taste, though it doesn’t have the same functionality as sweetness (the suggestion that something is good to eat) or bitterness (the warning that a food may be poisonous).
We have a very good idea of how taste receptors, in our mouths, detect sourness. That doesn’t mean it is particularly simple though. What happens is that a hydrogen ion (H+) enters the cell and essentially triggers an electrical response that fires the nerve that sends the signal to the brain that we are tasting something acidic.
There are a variety of different acids in food that influence our perception and enjoyment of it. Adding acids to foods (either more traditionally by using an acidic liquid like a juice, or in the more modern way of using them in powdered forms as food additives) is likely as old as cooking and the ideas of recipes. They also play a crucial role in preservation as well as providing some anti-oxidative properties.
Here are some of the key acids in food:
Acetic acid – We are most familiar with this acid as vinegar (though only acetic acid produced through fermentation can be called vinegar). This is an acid that can be extremely unpleasant (it is awful when present in coffee through defective processing), but we do like to add it to fried potatoes a lot.
Citric acid – This is the acid found in citrus fruit, and if you give most people plain water with citric acid added to it they will describe as tasting of lemons. This is an incredibly popular food additive – it is the acid used in sour sweets/candy – and it is no longer efficient to extract it from citrus fruit. Instead it is now often produced by fermenting a carbohydrate (like molasses) using a mould called Aspergillus niger.
Fumaric acid – This one doesn’t really occur in common foodstuffs (unless you enjoy eating lichen and Iceland moss), but it is used extensively as a food additive and acidity regulator. It is often used in soft drinks and can also be added as a coagulent in things like stovetop pudding mixes.
Lactic acid – Most of us are as familiar with the pain of lactic acid build up in muscles, as we are with the taste of it in sour milk products like yoghurt or cottage cheese, or with the sourness it brings to sourdough bread. Outside of food it also is used in things like detergents and as an active ingredient in mosquito lures.
Malic acid – This is the acid found in fruit like apples and pears, though for a more explicit experience of malic acid then the delicious tartness of rhubard is an excellent example. It was first isolated from apples, and as such takes its name from the latin malum. Despite being a little more expensive than citric acid, it is used in many similar products such as sodas (particularly diet ones) and also in the sourest of sour candies.
Phosphoric acid – This isn’t really a naturally occurring acid, but we consume huge amounts of the stuff, mostly in one particular form: cola. This particular type of acidity is often described as being relatively harsh compared to other acids, but it seems to provide excellent balance in cola drinks specifically.
Tartaric acid – This occurs naturally in many fruits like bananas, grapes and tamarinds. I confess I am probably most familiar with it as the primary acidity found in wine (along with citric, malic, ascorbic and many others).
Most of these acids can be bought easily in powdered form, and simple (low concentration!) solutions can be made for tasting. The tasting, and blind identification, of acids has become a staple part of coffee tasting tests for a variety of certifications.
There are a great deal of different acids in green coffee, byproducts of a cycle of chemical reactions called the Calvin Cycle. Some of these survive the roasting process intact, but many don’t. The longer and darker that a coffee is roasted the lower the perceived acidity tends to be when that coffee is brewed and tasted. This seems pretty simple – but when you dive into the chemistry a little bit you will see that it isn’t quite as simple as that.
A variety of the acids we’ve already mentioned (citric, acetic, lactic, malic and phosphoric) have been identified in brewed coffee, but two others have as well (at higher concentrations than those already mentioned). They are:
Quinic Acid – While it usually is in crystalline form, quinic acids melts at around 160C and coffee that is being roasted will comfortably exceed these temperatures. It is considered to add a positive acidity to the cup, and give coffees a “clean finish”.
Chlorogenic Acids (CGAs) - Chlorogenic acids (a group of acids, rather than just one) contain no chlorine. The name comes from the Greek χλωρός (light green) and -γένος (a suffix meaning “giving rise to”), because of the green colour produced when chlorogenic acids are oxidised. These acids play an important role in the generation of flavours during the roasting process.
CGAs degrade quite dramatically during the roasting process, with around 50% of them gone by the time a medium roast is reached. As CGAs break down the byproducts are both caffeic acid and quinic acid.
This is designed as only a brief introduction, but we all want to go deeper…
Now it is your turn! Submit a link to further reading on acidity, and vote for whichever topic you would to see focused on next. The link can be about acidity in coffee specifically, or about acidity in general. It can be examples of tastings to try, or more about how we taste and how acidity interacts with other tastes and flavours. Anything and everything!
Here are the links submitted by readers, for those interested in learning more about acidity:
What is acidity in regards to the taste of coffee?
Coffee Chemistry Acids
Low Acidity Coffee Reviews
“Coffee Gone Sour”
A pinch of salt in your coffee, sir?
Brew temperature – 180 vs 200
Sourness and Acidity
Coffee and acidity: the science and experience
Coffee Chemistry – Acidity
Teaching to Taste
What’s geology got to do with it?
Prufrock – Coffee Science
I found my “roots” to coffee in Africa
Effect of sugar on acid perception in wine (abstract)
A Structural Basis for the Biosynthesis of the Major Chlorogenic Acids Found in Coffee (full)
Alchemy in the roasting lab (pdf)
Improving the flavour of fruit products with acidulants (pdf)
Taste Receptors in the Gastrointestinal Tract III. Salty and sour taste: sensing of sodium and protons by the tongue (full)
Biosynthesis of Chlorogenic Acids in Growing and Ripening Fruits of Coffea arabica and Coffea canephora Plants (pdf full)
Nyeri is a county in Kenya that produces some of the stunning coffees we’ve come to love. Coffee in the region is generally produced by small holders, rather than larger estates, which means we are used to seeing traceability down to the local factories (the term used in Kenya for a wet mill) that farmer’s societies choose to work with.
Recent changes to Kenya’s political structure has given more power to local counties, and in Nyeri there has been a proposed change that is worrying. The governor of the county, Nderitu Gachagua, has announced that all of the coffee in the region shall be milled at a single mill (called Sagana) and the coffee should be pooled and sold through a newly formed company. The logic behind this is that the politicians believe that they can achieve higher prices for the coffee and pass those higher prices on to the producers. From a political perspective it should be noted that farmers are often the target of political manoeuvring in areas where they make up a large portion of the voter base, and this is very much the case in Nyeri.
While great Kenyan coffees produced by the mills throughout Nyeri can already be quite expensive, compared to many other sources of green coffee, there have long been challenges in making sure that the premiums achieved make their way to the producers. This is not a universal problem, by any means, but something that many producers are aware of. However I don’t think that reduced traceability like this, or pushing all of the coffee through one mill, will preserve the interests of growers who produce the highest quality coffee in the region. As a roaster, the idea of offering a coffee traceable simply down to Nyeri isn’t strongly appealing – and there several other regions in Central Kenya (and increasingly west of the Rift Valley) growing great coffees, with sufficient traceability. As traceability is a core tenet of my business this must factor into decision making and purchasing.
In an effort to further the political cause the Central Kenyan Coffee Mill (familiar to a great many speciality buyers) has essentially been shut down, and I’m sure I’m not alone in being extremely skeptical as to why and how this has been done.
While I am sure this centralising move does have some support in the farmer base, I do not think it is in the best interests of every farmer. 13 farmers’ societies have taken this to court to get an injunction, though their case won’t be heard until February 10th. That isn’t the best news considering the harvest has started.
As I’m based in Europe I suppose I should be looking to my trade association (SCAE) for advocacy and support in a situation like this, but I don’t think this will happen. Realistically I am hoping that the SCAA may have some opportunity to support the idea of retaining better levels of traceability. I’m sure we’ll see more information on this shared soon, but I thought spreading the word was a good idea.
In summary, I’m concerned that we’re going to lose some traceability (and potentially quality through separation) from some of the best coffees in the world. I’m concerned that legal wrangling, even best case scenario, could several delay the export of those coffees (not something anyone wants), and that this decision is being made my people who don’t really understand our sector of the market.
Mette- Marie Hansen also sent me this link. The whole thing is worth reading, but it is hard to ignore this bit.
The county government envisages a situation where once the coffee is milled, they can approach buyers and negotiate to supply either milled or roasted coffee at a premium price.
County Secretary for Agriculture Shadrack Mubea said earlier in the week that the governor was keen to explore potential markets, especially in non-traditional markets such as America and China.
Wilson Karime, the chairman of the Gititu Coffee Factory, which is under the four factory Aguthi Coffee Farmers Society, urged Nyeri farmers to give the governor a chance to prove his worth.
“The past model has favoured middlemen and buyers,” said Karime. “I see no harm in trying a new set if it finally benefits farmers.”
Emphasis added is mine. This is undeniably an approach that doesn’t understand the needs of speciality buyers, and doesn’t truly value quality.
I meet and chat to quite a lot of baristas and coffee people from all over the world. Often one of the topics that comes up is having a career in coffee and the idea of progressing. One of the most common avenues of conversation is learning, and I confess that from time to time the following sentence has been like a red rag to a bull:
“I think I am going to look for a job somewhere else, I don’t really feel like I am learning anything any more.”
To most people this may seem like a fair comment, but I want to explore the idea of learning at work and its purpose and value.
When you start your first serious coffee job (it might not be your first coffee job, but your first speciality coffee one) you go through a very intense learning experience. Learning like this feels great. Coffee seems big and exciting, and the learning is not only rapid but generally fun. Learning like this is very addictive and we all want to learn like this all the time, but that isn’t really viable – there’s work to do! We need to split the value of learning into two separate ideas here:
1. Learning is rewarding, and a motivating factor in performing and remaining in a job. The idea of mastery was best communicated to me by Daniel Pink in Drive, which is a great read about how to retain staff and motivate them to do good work.
2. Learning is a way to increase the value of a staff member. If time/money/resource has been spent on a staff member then, from a purely business perspective, this person should be able to generate more revenue and value as a result. In the simplest terms, if I teach you to brew espresso you go from being completely useless to a successful cafe, to someone who can produce products for sale. The more I train you then the more product you should be able to produce (you get faster and more efficient) or the more revenue you can generate (you can make more expensive drinks or upsell, or do good customer retention work).
The second type of learning is the responsibility of the business, to assess whether you are ready to learn more (you have achieved some level of mastery of your existing skillset) and then to deliver more training. After this there is a period of time when you should be mastering the new skills. Then there needs to be a period of time where you return on the investment of the employer. If you take your new skills and jump into a different job then the employer has no return on their investment. This will increasingly discourage them from further investment in staff, and over time lead to a stagnant work environment. Alternatively there may be requests for learning from staff, but no way for the business to recoup its investment as the learning may not have a practical application to that business.
The problem many people have is that in the period where you leverage your new skills for your employer, you generally stop learning. So you feel uninspired, restless and you start to look for other employment. I will accept that (and I include myself in this too) employers often do a bad job of setting out goals to met and expected time periods between the periods of advancement. (And in fairness to them, this is no easy thing to do).
This isn’t the only part of this that I find frustrating. Learning does not need to be passive. If you want to learn then there is a world of information out there, and a little effort will yield big reward. Staff who are active learners stand out very clearly in any business, not simply because of their demonstrated motivation. For quite some time I suffered mild imposter syndrome, because I felt that people thought I knew lots and all I had done is read things that had been published for free on the internet – something freely available to all. I should add that while I am pro active learning, I’m not a big believer in work cultures that expect you to stay late and be in early for no extra financial reward, in order to move up in an organisation.
My point here is not to try to generate sympathy for employers, but instead to try to encourage more active learning. This leads me to one of the things I’d like to do on the blog this year.
Here is what I am proposing: a monthly topic of learning that allows people to get involved with it. The plan will be:
Month 1 (this month): Write a short introductory blog post on a certain topic (approx 1000 words). This will also have a link allowing you to submit an interesting link on this topic. When you’ve submitted a link you will then get to vote on which topic we cover the following month.
Month 2: Republish the initial blog post including all of the submitted links on the topic. Publish a short introductory topic on the group voted subject. Again, submit a link on it to vote on what we do next.
My goal would be to continue this same cycle month to month throughout 2014 (thus covering 12 topics).
I have no idea if it will work, but if it does it will be fun to take a journey around different topics and to not know where we’re going until we get there. It will certainly push me, and I hope others will benefit too.
If you think this sounds fun then do please get involved. When the first topic goes live please share it (the more incoming and suggested reading the better!), and any feedback is welcome on twitter.