I was having a discussion with Jenni Field (@jmfield) on The Twitters this morning, where she wrote that she tried a new technique with coffee called "blooming," and that she was a believer in it. What followed was an interrogation that spanned at least a baker's dozen tweets about what the method was and how it might work, and I'm reasonably confident that I understand many of the secrets of this method.
The first thing I had to find out was if this was a water blooming or a heat blooming. Gelatin blooms by putting it in water, but spices bloom by heating them up. And while coffee is more like a spice than it is like gelatin, I suspected the term was being used somewhat metaphorically. In fact, the way to bloom coffee is to put a cup of under-boiling water into the grounds and let it sit a minute before doing the brew.
But what kind of brew? This is a method for an automatic drip coffee maker, which gave me the major clue I needed to understand what was going on. With an automatic drip coffee maker, you'll find when you are done with the brewing, the coffee grounds have depressions in the surface where the water dripped down. It's one of the major weaknesses with the method, because some of the coffee grounds gets extracted more quickly than rest. When you over-extract coffee, instead of flavor you get bitterness. With generations of people raised on automatic drip coffee, people associated "strong" coffee with bitter coffee. (The fact that the coffee was pre-ground did a lot to reinforce this belief.)
So you take your coffee grounds and pour in your hot, but not too h ot, water, which is just enough to soak the grounds without pouring through. The grounds settle, and then you run the automatic drip machine through its paces. What you find is that, at the end of the brewing cycle, you don't have those depressions from where the drip hit, instead, the coffee will pool at the top of the grounds and then soak through, kind of like when it rains on clay-thick ground. This gives you a more even extraction, and consequently better coffee.
Jenni noted that this kind of defeats the purpose of the automatic drip, as it's now much less automatic, and she postulated about a hypothetical new breed of coffee making machines that bloom automatically for better coffee. I think this would be great, but I have a feeling that this is either not feasible with automatic drip machines, or it's going to be prohibitively expensive.
I should warn you, what follows is going to be an in-depth exploration of the machinery of coffee making. If you're mostly concerned about the method of blooming, we're covered with what's above. Now it's all me time.
Ideally, the coffee maker would work in two stages: the first wold put in one cup of water and wait a minute, and the second would just brew as usual. And if the water spreads throughout the grounds from that first cup, then perfect. However, because the automatic drip tends to focus on a few spots, it's likely that the water would start going through the coffee and into the pot relatively quickly. If you could close off the chamber for the first round, then release it for the second bloom, them you'd have a better chance of this working.
Unfortunately, automatic drip coffee makers are extremely efficient devices that don't require any moving parts. They are very clever, but their cleverness means that, if you want to add a moving part, that you will raise the cost of the machine considerably compared to others of its kind. For an explanation of what happens in an automatic drip coffee maker, let's watch one of these videos by Bill Hammack. You'll see the video at the top of the article.
I'm not suggesting this is an impossible problem to solve, but I wonder how many coffee machine manufacturers are going to think that the customers of automatic drip coffeemakers will care? The brilliance of the automatic drip machine is in its engineering and its convenience, not its flavor. I prefer espresso or French Press for my coffee, and Michael Ruhlman prefers the old-fashioned percolator.