going a little inside baseball here …
we have talked a lot, on this blog and elsewhere, about our renewed “commitment to quality.” it’s at the core of what we do, and even narrower the commitment to coffee quality is the core of that. over the last 18 months, we’ve audited every part of our coffee process to ensure we’re being true to our craft. in what i hope will be a series of posts, i will dig a little deeper into some of the hiccups we encountered (i hate having the hiccups), and furthermore some of the changes we’ve made.
while each of us brews our coffee manually at home — this is to say, via a pour over or a chemex, an aeropress or a french press — we all drink coffee from our batch brewer in our summit stores. while this method works, and we stand by it, we found our consistency fluctuated day to day, hour to hour. so we broke it down and analyzed each variable in the brewing process.
ultimately, brewing coffee comes down to some pretty scientific stuff. the golden cup coffee standard, as specified by the specialty coffee association of america (scaa), measures both the concentration and yield of solubles. only 30% of a coffee bean can actually be extracted, where water acts as the solvent. what we need to do is make sure we extract only 18-22% of the coffee — anything between 22-30% is what we call “over-extracted,” and lends a bitter taste. anything between 0-18% is “under-extracted,” which tends to taste sour.
the variables at play in brewing coffee are pretty straightforward: coffee/water ratio, water temperature, grind size and brew time. we found that our coffee/water ratio was just a touch off, so if any other variable was off, our coffee tended to taste bitter. the other variable that was a bit off, and perhaps the most important, was our grind size. our particles of ground coffee tended to be too fine, so the water interacted with the ground coffee for too long.
all this is to say we refined our standard coffee/water ratio (320 grams for 1.5 gallons of water), bought a more precise grinder and dialed it in to the exact right size, and then made sure we were brewing at the right temperature (195-205 degrees). we think the end result is a great cup of drip coffee, and a consistently great cup. if you have any more questions about brewing, email me at [email protected] – i love to share what we’ve learned.