Ground Coffee

Apr 28, 2017

One of the founding principles of our business has been to never sell ground coffee. We apply this principle to both our retail and wholesale customers and have stood by this belief since we established Carvetii back in 2011. To accompany this principle we always write the ‘roasted on’ date on our bags and advise our customers to use the coffee within one month of roasting. This principle was laid down after a period of testing at the Roastery, along with plenty of research, and is aimed at ensuring that our customers receive our coffee in the best possible condition.

This principle does mean that some people are not able to use our coffee at home without investing in a grinder. Others really don’t want the hassle of grinding their own coffee and would choose to buy ground coffee. In some instances, retailers will not stock our coffee because we do not offer it in ground form. While this inevitably prevents us from making sales to these individuals, we cannot bring ourselves to sell our coffee in ground form.

The point of buying speciality coffee with a clear provenance is that, when roasted, you can clearly taste the flavours and characteristics which are a result of the growing and processing on the farm/mill. Our approach to roasting coffee allows these characteristics to come to the fore. However, these flavours are volatile in nature; in other words they are affected by oxygen. Exposure to the air for any period of time will degrade these volatile compounds. In bean form, only the outside of the coffee is exposed to oxygen, while in ground form, a much greater surface areas is exposed, and therefore the coffee degrades quicker.

Even in bean form, we have a relatively short shelf-life on our coffee. When we pack our coffee, we cannot guarantee the atmosphere in the bag is oxygen free and therefore the beans will slowly be affected by any residual oxygen which remains. It is possible to nitrogen-flush bags of coffee to remove all traces of oxygen but this adds another process which we feel is unnecessary.  If we ground our coffee, the residual oxygen in the bag would have an even greater impact, and it is likely that our customers would not experience the coffee in its best possible condition.

Nitrogen flushing, a preservation process common in the food industry, has its issues when it comes to coffee: once the bag has been opened, the coffee inside has been exposed to the air and therefore is likely to degrade very quickly. No nitrogen flushing can protect the coffee once the bag has been opened. Given that a typical 250g bag of coffee contains around eighteen servings (at 14g per serving), at a rate of one coffee per day, the grounds would be exposed to oxygen for nearly three weeks.

We are now seeing ground coffee appearing locally on shelves with a three month shelf-life, and it is highly unlikely that this coffee has been nitrogen flushed. While on the one hand I can understand the desire to get a product onto shelves (we have been faced with this dilemma many times), there seems to be an inconsistent message here. The Specialty Coffee Association of America states:

specialty1 can only occur when all of those involved in the coffee value chain work in harmony and maintain a keen focus on standards and excellence from start to finish

It’s the use of the term ‘excellence’ here that is pertinent when it comes to ground coffee. Without some form of preservation, is it possible to deliver an excellent product to the customer when it exists in ground form?

Putting it to the test?

Not one to rest on our laurels, we’ve designed a little experiment to put this to the test. A couple of weeks ago we saved three bags of coffee from the same roast, packaging them in the same bags we would use for retail sales. Around three weeks after roasting we’re going to brew each of these coffees in order to determine the effect of grinding. Given that we’re seeing coffee on the shelves with a three month lifespan, this timescale is relatively short, but we’re also going to repeat the test a week after opening the coffee. The bags are as follows:

In the first bag we’ve packaged the coffee in the same way we normally would. The coffee is in whole bean form and will be exactly as we would send out to our customers. We’ll be grinding this coffee just before we brew it, and we’ll only be grinding enough for that particular session. The coffee will then be stored in its bag for a week before we taste it again.

The second bag also contains coffee in whole bean form. However, a day before the brewing we’re going to grind the whole bag of coffee. This process replicates a customer who asks a coffee shop to grind the coffee for them. There is an honesty in this transaction: the customer buys the coffee in whole bean form but then asks for it to be ground; they are very much aware of when the coffee is ground. This coffee will also be stored in its original packaging until the second tasting a week later.

The third bag contains ground coffee. We ground this coffee on the day of roasting and just before we packed it and sealed it. This replicates a bag of ground coffee which sits on the shelf waiting for a customer to buy it. As with the other two, we’ll be keeping the coffee in its original packaging until the second tasting a week later.

To avoid too much bias when it comes to the tasting, we’ll be cupping the coffees blind. In other words, at the time of tasting we won’t know which coffee we’re actually trying. We’ll write up the results on this blog once both tasting sessions have been completed.

  1. We use the term ‘speciality’ in the UK, while in the US the term ‘specialty’ is used ↩