Labor Day Offtopic: Microroasting Coffee

Labor Day is coming up on Monday. Friday is also a Cadence holiday and Breakfast Bytes will not appear. So today is the last post before a holiday, and as always I write about something non-electronic. Today, coffee.

Microroasting sounds like something that might go on in the diffusion oven of a small fab. But actually, I’m talking about coffee roasting. I’ve learned how to talk the talk. My brother in London owns a couple of coffee roasting machines. Other friends have given me coffee that they roasted themselves. Yes, roasting your own coffee in your kitchen really is a thing (although I don't own a roaster, I just buy high-quality beans).

Third-Wave Coffee Shops

The hippest coffee shops are known as "third-wave coffee shops" as opposed to first-wave (old coffee shops that didn't pay much attention to coffee), or second-wave, such as Starbucks and Peets. The two near where I used to live in the San Francisco Misson District are Ritual Roasters and Four Barrel Coffee. They both roast all their own beans. Four Barrel Coffee uses a 1957 steampunk-looking German roasting machine that is in the shop so you can watch it (see the picture). Ritual Roasters used to do the same, with a similar-looking old roasting machine, but they ran out of space and so moved it out so they could get more tables in. Both shops are too hip to have public WiFi. It's about coffee and conversation, not sitting around doing your email. Blue Bottle Coffee, whose coffee shops contain strange types of glassware to make coffee in ways you’ve never tried, also roast all their own beans.

These are all known as “micro-roasters” who roast small batches of high-quality coffee from single farms; Starbucks and Peet’s only manage to have a country of origin since they need such large quantities. If you go to a ball game in San Francisco or come up to the city by Caltrain, then the Creamery, just across the road from the Caltrain station, also serves Ritual Roasters coffee (and it’s just a block from where I lived before the Mission, which used to be really convenient). The quality of the coffee at any of these places is immeasurably better than the average restaurant espresso machine or Starbucks. The first time you have a well-made espresso made from perfectly and recently roasted beans, it is a revelation.

Coffee Roasting

Basically the way you roast beans is to apply heat while they are tumbled until they reach the desired level of doneness, then you cool them down as fast as you can so they don’t continue roasting. One problem is that in the middle of the process, the chemical reactions that the heat induces in the coffee become exothermic, or an alternative theory is that once all the water has been driven off the temperature can rise uncontrollably fast. It is a major problem in roasting that you will have fires when the roasting process runs away. My brother had his first fire last year. Apparently, it is a rite of passage if you roast your own beans.

There are two critical points in roasting, known as first crack and second crack. These are points in the roasting when you can actually hear the beans crack and indicate a certain point in the roasting. Actually it is pretty hard to hear the cracks in a home roasting machine which noisily blasts hot air through the beans, but coffee roasters all talk about these points since they are well defined. Pros regard these, along with aroma, as a more useful way to assess doneness than color. Beans are roasted to "first crack is complete” or until "first snaps of second crack" and so on. So if you really want to bluff your way in coffee roasting, these are great terms to drop into the conversation!

Green unroasted beans do not deteriorate for about a year. Roasted beans start to deteriorate almost immediately. For the ultimate in coffee, you want beans roasted no more than a week or two earlier, and only ground just before the coffee is made. Once roasted, coffee beans produce carbon dioxide. You’ll find if you put freshly roasted beans in a ziplock bag that the bag starts to expand. In a fresh espresso, that gas coming out during the brewing process is what makes the characteristic crema on top of the coffee and gives it its beguiling aroma. Old coffee doesn’t do that since it has outgassed all the carbon dioxide already.

If you want to know more about roasting, including lots of pictures of coffee beans through the process, then take a look at this roasting guide.

Making Coffee at Home

One thing my brother uses to make coffee (which I use, too) is something called the "clever coffee dripper". As you can see from the picture, it looks a bit like a normal filter coffee cone. The thing that makes it "clever" is that when it is on a flat surface, the bottom is sealed and nothing runs out. So you add the water to the coffee, wait an appropriate length of time (my brother uses a timer, of course). When you put the dripper on top of a cup, it pushes in the base, opens the valve, and all the coffee runs through into the cup. So it is a sort of combination of a normal filter coffee cone, and a French press, with the advantages of both.

Another good alternative, that I used to use, is an Aeropress. It makes great coffee but it is more of a pain to keep clean.

I'm not an expert like my brother. I've never been on a weekend-long coffee course. But the one piece of advice I have is that you should get a coffee grinder, and grind the beans just before you make coffee. None of the other stuff (ration, time, brew method) matters so much compared to having freshly ground beans.

My brother's advice?

For the Clever Dripper we use, which is a combination of a filter and a drip, 24g of coffee and 240g of water, 3 minutes, resulting in 220g of coffee in the cup, which is quite strong. For my espresso machine, 13g of coffee, 10s pre-infusion and about 18s pull, resulting in about 30g of espresso. I’m much more iffy about the espresso than the Dripper where it really doesn’t matter all that much. I’ve been in various Facebook groups for coffee for a while, and really guys, you can take this too seriously!

Or to learn more about how to make the perfect cup of coffee at home, here are two ten-minute videos (one on basics, and one on espresso drinks):

Next time you are in the city, wear a mask and treat yourself to the ultimate cup of coffee. Unfortunately, there doesn't seem to be a coffee shop like that near where I live, nor near Cadence (not that I've been to the Cadence office since early March).

Labor Day

Traditionally, Labor Day is the end of summer. This always seemed a bit weird since I live in California—summer goes on a lot longer and we don't normally get rain until November. But in much of the US the summer heat cools off and it is not that long until the first frost in October, or even late September if you live somewhere like Minnesota.

So, wherever you are, enjoy your Labor Day. Breakfast Bytes will be back on Tuesday.

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