barry wrote:how many shots did you pull at each temp, and was the taste profile consistent across those shots?

I pulled shots over three sessions for each coffee.
In each case I pulled four shots at a set temp (unless I had a shot that either channelled or looked wrong in which case I'd discard and repeat). In most cases I was able to count all four of these shots though, as noted earlier, every once and a while I would get an "off" scoring shot which I would then discard when calculating averages.

I probably should have pulled more shots at each temp but I don't think I could have coped with that amount of coffee. Plus, as it was, I burned through something like 3 pounds of each of the Hairbender and the Artigiano Espresso.

okay... i just wanted to make sure that the differences couldn't be attributed to variation in blend component distribution.

Good point.
I'd not considered that.

I obviously need to repeat the test with an SO espresso.
Yikes. I need another tasting volunteer.

I wonder if bean component distribution would explain some of the random "off" scoring shots that looked fine when extracting... Hmm...

what you might be seeing is an effect of additive taste components (think wave theory). if different tastes come out at different temps, or if the quantity of tastes varies with temp, then perhaps the tastes are additive and subtractive so the resultant flavor peaks vary with temperature, even though all the flavors are there. it sounds like i need to find access to some chromatography equipment.

--barry "just guessing"

barry wrote:okay... i just wanted to make sure that the differences couldn't be attributed to variation in blend component distribution.

How do you control that?...make sure you mix well when blending?

With discrete items like beans does the "ratio" in the blend go south when you grind a small number of beans such as many of us do when we are only making 1 shot?


Sean

barry wrote:okay... i just wanted to make sure that the differences couldn't be attributed to variation in blend component distribution.

I was thinking the same thing. You rock, Barr-Barr.

lennoncs wrote:How do you control that?...make sure you mix well when blending?

This is something that people don't spend nearly enough time thinking about. This is why folks should be wary when you see someone who says that their espresso blend contains 7 or more varieties of arabica, or whatever.

The more types of beans you have, the higher the probability that one or more of the varieties actually won't make it into a particular double-shot, or other such problems. 5 varieties is usually the upper-limit of what's practical.

Tacy... S.O.S. away... but keep in mind, even then... there are still gonna be variations among the coffee beans. Perhaps a little too much science and not enough art, eh?

lennoncs wrote:How do you control that?

you don't. it's a probability issue. any time you have more than one bean type, there will be variation in the relative proportions for any given sample size.

if you blend up 100lbs of Blend A, with 50% X, 25% Y, and 25% Z, then you can only be assured of that proportion at that batch size. if you pull a 10lb aliquot from that 100lb batch, you cannot be assured of the same proportion, no matter how well it has been mixed. pull an 18 gram sample, and, well, you can assume some variation from shot to shot. note that this problem is exacerbated by any increase in the number of components; it is less of an issue for a two-bean blend than for a ten-bean blend.

someplace i have the mathematics behind this... it was a topic of discussion on a.c a number of years ago, and i think david ross and i continued the math into email.

Nick nick nick...
Unless someone has done a poor job with their cupping and sourcing, the odds of you having discernable variance in a group of shots of an SO espresso are really low (statistically relevant, yes, but very low).
This is why we cup all samples in multiple cups and over multiple flights before purchasing.
Now obvioiusly I'm not going to use a coffee where such variance is accepted (yemeni coffees, some ethiopian coffees) but rather a washed central or the like where inconsistency would be grounds for rejecting a lot).

lennoncs wrote:
How do you control that?...make sure you mix well when blending?

1 - don't use more than 5 beans in a blend,
2 - cup and evaluate coffees well to choose only very consistent beans for your blend,
3 - accept some variance (it's unavoidable).