I know I rail on this a lot, but I think it's important.
Isaiah and Garth went to the regional barista competition (SCRBC) the weekend before last, and they experienced the same thing as usual. They really went this year trying to play the game. They changed almost everything about the way we make coffee in order to follow the strict and unbending rules laid out by the... whoever. I'm not sure who came up with these rules. Intelligentsia?
One of the many reasons I dislike the barista competitions is that I see them quelling the creativity and individuality in the industry. It SHOULD be that things are done slightly different at every shop you walk into. Heck, each of my employees have creative freedom to put their own spin on the way we make coffee. And occasionally we change the way we do things because one of them found a better way. This doesn't happen at the barista comps. If someone does something even SLIGHTLY different, they are penalized and berated by the "judges." And we see people who do things we love, change those things because they are told they are doing it wrong. But, as Isaiah always says, it should be in the cup. If it's good in the cup, you did it right.
One of the things looked down upon in the specialty coffee industry is the way we tamp. We tamp as hard as we can. Who taught me that? No one taught me that. I started noticing years ago that the harder I tamped, the sweeter the coffee tasted. And I like that. Hard tamp = sweet espresso. I promise you that's true. I'm not exactly sure why.
At the comp, my boys always get marked down for crema that's not the color the judges are looking for and the crema doesn't persist as long as they want it to. They always say our coffee is "too fresh." I'm not kidding about that. As soon as we get the score sheets, I'll post them so you can see it for yourself. The coffee is too fresh? Yeah yeah, we've been through this. Well, I have a couple theories about all this. And I think as time goes on, you're going to see that I'm right. Because I learned it, not from Intelli, but from experience and experiments.
So listen to this.
Basically crema is a bunch of small oil bubbles with carbon dioxide inside them. The carbon dioxide exists in the coffee bean after roasting and preserves the oil, protecting it from oxygen which causes the oils to go rancid. The carbon dioxide contains the fresh coffee smell that we all love. So when the coffee is fresh, before it has "degassed," espresso will have crema composed of fresh coffee oils containing carbon dioxide and that beautiful aroma. Because ambient air around the fresh crema contains a lot of different elements and the crema contains mostly co2, it would make sense to me that there is a pressure difference and the crema won't persist as long. When the coffee degasses, the co2 is replaced by ambient air. The oxygen in the ambient air reacts with the coffee oils causing them to go rancid. When you make espresso with degassed coffee, the crema should be rancid oil with ambient air inside. At this point there will be no pressure difference and no reason the crema should dissipate from an air pressure standpoint. So if coffee freshness (and deliciousness) causes crema to dissipate faster, I say crema persistence should be considered a negative.
Secondly, I was reading David Schomer's blog the other day. We often wonder around here where David Schomer has disappeared to. He was one of the original influences on the technique I developed in making espresso. I really respect him for consistently testing and making discoveries about espresso and coffee. He's definitely a smart guy. I don't agree with everything he says and does, but I respect his opinions because I feel that they are based on testing and sound judgments.
In Schomer's blog entry he was saying that they took a monsooned robusta out of their espresso blend, and in doing so the espresso became much sweeter. Another thing that happened was the crema began to dissipate much faster. He called a friend of his who is a food scientist and they guy told him that the increased sugar content in the espresso would have a negative effect on crema life. The sugars break the long-chain surfactant molecules responsible for stable crema. That's what Schomer says. Again, if sweetness in espresso causes crema to dissipate faster, it seems that crema persistence should at least be irrelevant and at most be considered a bad thing.
Another thing he talked about in his blog is the flow rate. When he took the monsooned coffee out of their blend, the overall moisture content of the blend went up and they had to increase the grind size to account for this. When the grind size was smaller, micro-particles would migrate downward during the brew cycle and eventually choke the shot. He says by using a larger grind size, there are less of these micro-particles and they don't have the choking problem. Thus, they have a much greater control over flow rate and when to end the shot. And Schomer says that is a "truly dominant factor in a perfect cup."
I harken back. Harder tamp, coarser grind, less micro-particles, more control over shots, sweeter espresso.
Sweeter espresso, fresh coffee, less crema persistence.
Should we really concern ourselves so much with crema persistence?
Just drink it when I give it to you.
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