HomeRoast Digest

Topic: was Dual boiler espresso machine- (5 msgs / 492 lines)
1) From: Tom Ulmer
Starting from boiler temperature control... =
The discussion is not whether temperature will play a factor but rather
anyone can blindly distinguish a difference in 1F from one pull to an=
when there are so many other factors that can affect taste. Obviously one
can determine whether a particular shot is more agreeable in taste than
another but to say this shot pulled 1 cooler or hotter is better simply
because of temperature seems far-fetched in my opinion. More believable to
me is a confluence all variables coming together to produce a tasty shot.
With this said, I am sure there is a temperature range where blind
determination solely by temperature is possible.
Certainly if one has obsessed enough at .1F intervals in search of optim=
flavor it may be a very short step to convince the mind .01F increments
would be better.

2) From: Mike Chester
I think that you have missed the point that miKe, Plain Mike, Tom, and =
others have been trying to make.  No one has said that temperature is the =
only variable that matters.  In fact everyone has stated that all of the =
variables you mention are valid.  The point that they have been making and =
you seem to be missing is that in order to determine the effect of a =
particular variable on shot flavor, it is necessary to hold the other =
variables to a constant value.  If for example, you wanted to measure the =
effect of grind, you would need to keep the temp, pull length, pressure, =
etc. constant.  To measure the effect of temperature, you would need to kee=
p =
the other variables constant.  You seem to be saying that if you change =
every variable, you would not know if the difference in taste came from =
temperature or some other variable and that is the point that everyone was =
trying to make.  The different variables do interact somewhat, so a =
knowledgeable person can compensate somewhat if one variable is off a bit, =
but the goal is consistency in all of the variables.  There is not a set =
formula for the perfect shot.  Aside from personal preferences, different =
people may come up with a different set of variables.  Do the differences i=
n =
individual machines, measuring equipment, elevation above sea level, etc. =
Your "ideal" temperature may be different for a particular blend or SO than =
mine, but the important thing is that you are satisfied.  What I, or anyone =
else thinks of your drink is irrelevant.
Mike Chester

3) From: Tom Ulmer
While I do appreciate you trying to explain this from another angle I have
not missed their point. What I think I'm attempting to say but quite plainly
I am not communicating is - in my opinion - controlling the other variables
to the same precision as a single degree F of temperature is not easily
quantified - much less duplicated - in order to make a shot to shot blind
taste comparison based solely on 1F.
Certainly there are those who with some dedication to the task may detect
the subtle differences across increments in temperature with a given coffee
and conditions. There are some I would imagine this taste memory is lasting
for some span of time in reasonable detail. For anyone to be able to blindly
determine the shot temperature by taste with accuracy is beyond my belief.
My mind is open to the possibility however mere snobbery is not convincing. =

4) From: Scace, Gregory E. Mr.
I performed the thermal measurements and analysis for the WBC machine selec=
tion trials that were held in Vancouver 2008.  The week-long exercise start=
ed by measuring shot to shot reproducibility of the candidate machines, and=
 then finished with teams of world-class baristas (including heather Perry =
and james Hoffman), and coffee professionals providing qualitative feedback=
 on each of the machines.  The temperature data was kept secret during the =
tests.  At the end, all of the candidates were ranked by first qualifying t=
hem based on thermal reproducibility (they had to meet a minimum level of r=
eproducibility), then based on their useability.  Interestingly enuff to me=
, the machines that were most highly rated by the test groups were the ones=
 with temperature reproducibility at the 1 degree F level or better.  Once =
that level of stability was achieved, ergonomics and machine idiosyncrasies=
 began to drive the ranking order.  Just for grins we ran some tests of a c=
ouple machines that featured individually adjustable group temperatures, se=
tting each group to a different temperature in increments of 1 degree.  You=
 can certainly taste differences.  The differences are not so large that on=
e shot sucks while the other is amazing, but the differences are there.  =
As far as I'm concerned, at the current level of machine sophistication one=
 degree is about the right threshold value at which temperature control and=
 stability becomes relatively unimportant compared to other parameter incon=
sistencies.  =

5) From: Tom & Maria - Sweet Maria's Coffee
Personally, I am a realist who believes in bringing all these =
variables under a reasonable measure of control to produce something =
of repeatably good quality. As people who make coffee, we become =
incrementally more demanding as time goes on and we further define =
what we like, and what it takes to produce it. At one time a hand =
pull Pavoni and a Silvia were great for most of us but they might not =
be now for a few reasons: 1 -patience and skill level. I have =
limitations on both. 2 - limitations of the machine that can be only =
partially overcome with modification 3- something else comes along =
that is just a better starting point, a better platform, and perhaps =
significantly 4. at one time a Silvia price is what we were willing =
to spend, and eventually we are willing to upsell ourselves on =
something better.
I know, I am just summing up the obvious. The fact is, I have made =
and can sometimes still make great shots from rustic equipment, and =
we here are still trying to figure out exactly where in all this the =
Silvia falls, because it still fits a price range that we can't find =
anything else to replace it with -( well, there are those 2 cheaper =
Isomac models but the company seems entirely lame when it comes to =
So back to Tom's U's point, I would respond that in a perfect world =
we can get all these variables under control to determine if 1 deg. =
actually matters, and in a way good coffee preparation is trying to =
do that, to the best of our ability and situation, each time we brew =
or pull a shot. But it's an imperfect world, and the phone rings, the =
kid is crying, we're late for something, OR, the grinder is =
misadjusted, the group head is a bit overheated, the gravitational =
forces are stronger ... we have to have a sense of humor about this, =
and appreciate the times when everything comes together for a really =
nice coffee. 1 degree f, 2 degrees, 3 degrees? It's hard to say. Add =
to it the fact that shots are variable anyway, roasts are slightly =
different, grind must be adjusted accordingly etc, it's a miracle we =
ever get one of those really stand-out shots at all. I know that a =
lot of shops have a little secret: 8.5 bars, or something just shy of =
9, to help pull sweeter, milder, less acidic shots, and perhaps it =
helps with minor problems in tamp, grind adj., clumping and =
distribution, etc. Who knows, but I see it a fair bit, and now have =
my lab machine at around 8.75-9  bars max, roughly.
-- =
"Great coffee comes from little roasters" - Sweet Maria's Home Coffee Roast=
               Thompson & Maria -http://www.sweetmarias.com     Sweet Maria's Coffee - 1115 21st Street, Oakland, CA 94607 - USA
             phone/fax: 888 876 5917 - info_at_sweetmarias.com
Homeroast mailing list
Homeroast community pictures -upload yours!) :http://www.sweetmariascoffee=.com/gallery/main.php?g2_itemId=7820

HomeRoast Digest