Transparency in measurements

Long time ago, when we started buying green coffee we relied on 1 thing and 1 thing only. Cupping the coffees. When it’s good you buy it, when it’s not you do not. Simple. Measurements were always an afterthought.  However, unfortunately, we learned the hard way cupping is not enough. That’s why we’d like to outline some parameters we started to rely on whilst buying green coffee. However we still work with our gut – we need these numbers to back us up or rethink why we are tasting certain things. 

#Roasters#transparancy

Below you can find the for us 3 most important measurements when we are buying green coffee, we’d like to share this in the future as transparency is very important for us & if the parameters aren’t right we’re not buying it and neither should you. So in the future if you ask for our offerlist we’ll give you an opportunity to cup our coffees (roasted or green), ask for the pricing parameters, info & pictures of the lot  & see their scores on the following parameters:

Density is mass divided by volume so gram / ml in our case. The perfect bean is 1 g/ 1 ml.

Parameters as Elevations, variety, processing (naturals are f.e. less dens than washed ones) etc all affect the density of the bean and hence the quality. Also the way you measure density is important, as it is for everything. We are not measuring the density with ‘the biting on them measurement ;-)’ however we’d like to note that the scores we provide you are indicators. Do not pin us on them. Density tells you a lot about quality and can help you with to determine the roasting style.
At the farm the first selection already starts through density (f.e. floaters) afterwards they keep selecting through the level of density (f.e. channels of flowing water) and at the dry mill (f.e. vibrating tables).

This one is probably the most obvious one and the most used for quality. We all know the golden rule of 12 %. There is also a reason this one is the most known, it’s the most important step in quality.
MC is the weight of water inside the coffee bean. When the fruit is picked it’s full of water, that needs to be dried until at least 12 % before it’s allowed to be shipped. How they dry is at least as important but let’s elaborate on this another time. 

W.A. is just as the 12 % rule of moisture content a term that is used more and more frequently though this one is really not so known yet. When the moisture content talks about the water that has left the bean, WA tells us more about what happens with the water still left inside the bean. 

Water activity measurements are expressed as a decimal. Water activity measurements of food will always be expressed as a numerical value less than one but greater than zero. Water activity readings may vary in reliability depending on the type of device in use, and these readings can be affected by temperature, relative humidity, and other parameters. But that’s often the case with coffee … there are so many parameters to take into account that it will be never exact science. That way we still need our sensory skills, and we can still feel usefull ;-). 

Why is it relevant?
Most important one is product safety. WA is a food safety indicator for years. When it’s below 0,6 food is generally safe. More will result in risks of Mold, contamination, fungus, … (aqualab https://www.metergroup.com/food/) 

The MOST IMPORTANT reason why you should measure W.A in specialty coffee is however for your shelf live! High WA kan predict moldy flavours in the future. If your water activity is higher than 0,60 you have a significant higher chance to get a coffee that looses it’s complex flavours and even turn moldy, baggy and aged. For us 0,6 is an indicator to not buy at all. Yes, we know there are a lot of parameters, again. Like temperature, humidity, grain pro, … however 0,6 is were we draw the line.

Does water activity affect roasting style? Probably, however this is less relevant. There are other parameters that should ask for your attention more than WA. The only real big study that linked the Maillard reaction & WA showed results when a coffee has a score of 0,7 or more, and believe me, those coffees you don’t want to have in your offer. So don’t focus on the correlation. (here is the study though if you’d like to read it for yourself https://link.springer.com/chapter/10.1007/978-1-4939-2578-0_4) 

However what we experienced is that coffees above 0,6 can taste REALLY nice & complex and will be a pleasure to roast (see study) however this party will not last long. So know for yourself what you want, if you’d like to have a coffee with interesting flavours and you’ll roast it on the spot, sure give it a go but we prefer to go for a more broader approach of great WA & great flavours…

 

If you have any questions drop us an e-mail at Laura@cup-a-lot.com!

 

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