Roasting Mechanics 101

Like most worthy endeavors, roasting coffee is an art honed over time. The basics of roasting are fairly simple, much more so than most people realize. In their raw state, coffee beans are hard, green and slightly chewy. As they roast, the begin to turn brown and expand, releasing their water content and opening up at the cellular level. They begin to crack and pop as they continue to expand and gas trapped inside the beans escapes. At this point, the beans become exothermic, generating their own heat, rapidly pushing up their internal temperatures. If the beans are allowed to continue heating up, eventually flavor oils will be forced out on to the surface of the beans and they will begin to caramelize, then burn.

Ideally, roasting equipment should enable the beans to progress through this process evenly and consistently, so that the beans all roast about the same rate and the roastmaster has predictability between roasts. Ideally. Since my roaster is home-made, it lacks some of the perks of professional roasting equipment, such a sample port that allows you to take out a few beans without interrupting the roast or a built in cooling pan that allows a rapid a transfer of the beans. However, because it is home-made, I also have the ability to upgrade it as my skills progress and my understanding of the elements of a good roast evolve. So, with a couple of weeks off from the markets, I have taken some time to rig a new and stronger motor that will turn the drum faster and more evenly. This should not only increase the consistency of my roasts but also the speed. But only time will tell.

Taming of the Brew

I am in the process of cobbling together a semi-comprehensive brew guide for my web site. (A preliminary version is now up.) As I am sure many of you have heard me say, my preferred brewing method is a manual pour-over. It is only slightly more work than using an auto-drip machine, but offers consistently superior results. However, that is not to say that this is the only method I use. I have used a number of methods including the Aeropress described below, which produced very good results during Erin's recent trip. I have also been using a French press a lot lately and a similar brewer known as an Eva Solo. In the not-so-distant past, I have experimented with a stove-top brewer known as either a vacuum pot or coffee siphon, which is finicky but can produce phenomenal results in experienced hands. There are several methods with which I am less familiar as well, such as the mokka pot, a stove-top device in which steam forces the hot water through fine grounds producing a very potent brew. Each of these techniques has its own advantages and disadvantages. Each also extracts a different flavor profile from the beans, which is one of the things that makes coffee so interesting and exciting. With more than 700 flavor constituents in a good-quality coffee, you can always find new ways to stimulate your taste buds. So the adventure continues.

From left to right: Aeropress, Eva Solo, French press, Vacuum pot.

Coffee A-Go-Go

My girlfriend headed off to Chicago this morning on business. Planning for her trip, she faced the age old question: "What if I can't find a decent coffee shop while I am away?" Okay, maybe it isn't age old, but it is one that I have been mulling over for some time now, ever since Erin came back from Memphis complaining that she couldn't find anything that had the caffeine kick she needed to get started in the mornings. Not wanting to take the blame again for having got her hooked on the high-octane stuff in the first place, I packed her off with a coffee kit containing several single-serving, air-tight vials of freshly roasted and ground coffee and a device called an Aeropress. The Aeropress (which gets it's name in part from the fact that it is marketed by Aerobie, the company that started by selling those ring-type non-Frisbee brand frisbees) has the advantages of being not only portable and hand operated, but also capable of brewing at relatively low temperatures. The latter feature is important in case the only access you have to hot water is an hotel-room auto-drip coffee machine. If you read my first posting you know, the average coffee machine rarely produces water much above 185 degrees. I'll be sure to let you know how it works out.