May 2018 Newsletter

Fundamentals are an often overlooked aspect of brewing coffee. I get a fair bit of correspondence from non-customers, usually from overseas, asking for solutions to brewing problems. In most cases the problems come down to mechanical failures in coffee brewers or ignorance of some fundamental aspect of brewing.

I thought it would be worthwhile to go over some of the simpler things that can cause problems, starting with good quality fresh roasted beans (of course). You can store beans in a sealed container for about 2 weeks, in a normal fridge freezer (-4°C) for 4 to 6 weeks, chest freezer (-18°C) for 3 months and dry ice temperature (-78°C) for up to a year.

Then comes grinding, and I'd say about half of all the problems I see are grind based. One of the most common espresso problems is simply not adjusting the grinder when the beans change, either by type, season or roast level. A slightly lighter roast needs a finer grind; slightly darker a coarser grind. Filter brewers can be more forgiving, but some of the latest models require precision grinding, as does the Aeropress.

The least grind sensitive brewing methods are plunger and syphon, because it's easy to adjust the brewing time to accommodate grind variations. That's another fundamental rule, the finer the grind the shorter the brewing time, with the exception being middle eastern coffee brewed in an Ibrik.

Finer grind equals greater surface area equals faster extraction. Of course, with filter brewing a finer grind may slow down the passage of coffee through the filter, lengthening the extraction time, which is why precision is needed. Overextraction leads to undesirable bitterness.

Temperature is the next fundamental variable. My personal preference is a water temperature between 88°C and 92°C, regardless of process, but again dependant on roast level. In my experience, very dark roasts extract best around 88°C, but very light "Scandinavian" roasts can require up to 96°C to get a drinkable result. Remember, this is the temperature of the water as it first contacts the ground coffee, and things will immediately get cooler. This is why I like Coffee Syphons so much, and all my "final" cupping for the specials is done with syphon brewed coffee.

Once you've standardized the grind, the temperature takes care of itself, allowing you to adjust the brewing time as necessary.

The final fundamental is origin, i.e. where is the coffee grown, and where did it originate. There is a new book, The Coffee Atlas of Ethiopia, by Dr. Aaron Davis and his Kew Gardens UK team which gets down to the DNA level of the origins of coffee. In his words, "Ethiopian Arabica DNA diversity has a distinct geographical pattern, which, in combination with the diverse local climates of each origin, yields a cornucopia of flavour profiles.. It became clear that there are many unique and interesting flavour experiences that are hardly known outside Ethiopia, and that there are several origins barely touched upon, if at all, by specialty coffee providers."

I'm incredibly envious. This month's special helps a bit, it's the stunning
Ethiopian Yirgacheffe Gedeb
$55.00
Relatively low acid, blueberries and stone fruit front palate with a long, rich cocoa finish.

Until next month
Alan