June 2021 Newsletter
Supply problems seem to be finally working themselves through the system, so we should be back to our "normal" range of coffees by the start of July. There are still large backlogged stocks of green coffees awaiting shipment from most producing countries, but the bare minimums are getting through.
Apart from relieving a lot of the stress involved in hunting down substitutes for unavailable coffees it will add just that little bit more flavour, aroma and freshness to the roasted results. While green coffees have a long lifespan, they do tend to deteriorate over time.
The deterioration tends to take the form of a loss of intensity in the final roasted product. Acidity, aroma and body are all just ... less. It doesn't necessarily make a particular coffee bad, but in cupping scores it can take an 89 point coffee down to an 81 over the course of a year or so. It's the reason so many high end coffees are grown, shipped, sold and roasted on a "just in time" basis.
Surprisingly, this has just been accepted as "the way things are" for a long time, without asking "why is it so?" Recently there's been a bit of research to try to figure out exactly what is happening, and why it happens.
It appears that one of the major factors in the deterioration of green coffee is its moisture content. Green coffee beans are seeds, and like most seeds they retain a certain amount of internal moisture so they can germinate. Coffee is shipped with a free moisture content between 10 to 13%. Green coffee beans have their own internal quota of microorganisms, which tend to do better in warm moist conditions.
"Doing better" means that they consume the sugars, aromatics and flavonoids, leaving behind the woody (cellulose) bits, so the coffee loses intensity. Roasting not only drives off the free moisture, it also produces water via chemical reactions. Generally we lose around 16% of the weight of green coffee going in to the roaster as steam and gases. Roasting also stops all microbial action inside the bean.
The conclusion is that storing green coffee at low temperature and moisture content may increase its "shelf life" substantially, but there are no precise figures to say how much. There may also be a lot of grower resistance to processing the coffees down to lower moisture content. It takes time and energy and the grower ends up with a lower weight of coffee to sell.
There are a lot of other questions yet to be answered, particularly about coffee processing. You'd expect washed and dry process coffees to have different rates of change, but what about processing that actually changes the types of microbes involved? Yeast fermented and carbonic macerated coffees would be examples of this. There are huge implications for the coffee supply chain, both in shipping and storage, once the chain creaks back into action.
Anyway, this month's special is both fresh and a fabulous coffee, guaranteed to make a superb espresso as well as other brewing methods.
$54 Per Kilogram
Medium
Zingy, sweet lemonade acidity with a smooth rich body and a soft peanut butter and chocolate finish. Absolutely yummy.
Depending on circumstances there might be a July newsletter and new special next month, if the boat comes in.
Until then,
Alan
