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Saturday, September 30, 2006

Dose variance...

Dosing numbers
I was thinking of dose variance numbers and what it means when you say acceptable variance. I have always thought of +-0.5 grams as being the ideal. It isn't until you get the scale out and really measure your variance that you can really grasp consistency in your dose. It's an issue right now because of a conversation I was having with a new friend from the west coast who discussed how some of his coworkers rather than tweak the grind would make small adjustments to the dose. I was shocked.. well not really...

First of all, lower doses mean you have more variance as a percentage of the whole. This does not mean a lower dose is worse but that it is harder to pull consistently. It is, look at the numbers! Even so, any consistent variation over 0.5 grams should be unacceptable.

I'm not advocating changing coffees to fit doses. I believe there are defined sweet spots for coffees at certain doses and sometimes we are just stuck with tricky doses. Barismo!

The lower your dose, the wider the variation in your shots. Sure we are talking a tiny amout but if anyone wants to do the numbers and see what those variances translate in volume changes and you realize how difficult you are making your life as a barista. But wait, I'm not advocating higher doses... well maybe just a little when you can get away with it. The higher doses meant that you could have a slightly greater variance and get away with it. Q:What is the difference between a 1 gram variation on a 22gram dose and a .5 gram variation on a 14 gram dose? A: 1 percent.

Imagine a 1 gram variation on 14 gram dose and the change that would have on the cup. That's a %7.14 plus or minus change in the cup. For a shot that is under 2 oz, that's a lot of change.

The thing I am really thinking about is how you can't measure your doses except when learning and so you have to have that feel for consistent dosing. It's fun when training when you can call your shots gram weight and then nail it for trainee but the truth is that you can show a person and show a person and they may not get it until they pull a thousand shots. You have to develop a feel for the coffee. Then there is the problem that arises from having the feel down for one coffee then being presented with another coffee of different density... Everything is turned on it's head.

Barista don't have scales to weigh every shot nor the time to do extended tamping routines with a line waiting. They have to have a routine based on feel.

I guess all that is in it's very essence why I believe in a dosing methodology where you keep your leveling methods the same but change to different volume baskets. It is all in the feel but if you want to leave the scale on the sidelines you gotta use different baskets so you don't have to alter your ritual.

Take the time to feel the grinds and weigh your dose a few times next time you pull shots.

-Jaime "I hate ridged baskets!!!" v.
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