HomeRoast Digest


Topic: A green coffee washing experiment (12 msgs / 286 lines)
1) From: Ken Mary
A measured quantity of Java Jampit was soaked in room temp water for 2 
hours, then rinsed in warm tap water. There was a large amount of chaff
being dislodged, so the rinse was continued with intermittent shaking and
rinsing to remove the chaff. The bean volume was increased by about 60%, so
a significant amount of water was absorbed. Color became a mottled
blue-grey. Excess water was removed with a paper towel and the beans were
allowed to dry at room temp for 2 hours. They were roasted in a popper to
just a few snaps into second crack, at 8.5 minutes, first crack at 5.0 to
6.5 minutes. There was nothing abnormal about the roast, no early smoke from
the excess water, no bad smells. In fact, the smell was pleasant through the
entire roast. I did not weigh the beans, not having a suitable scale. The
roast expansion was 70% based on the original green, this is normal for my
roasts. The first brew made 4 hours later was very good and smooth. The
second brew after about 15 hours aging was very good with increased body and
complexity.
So my conclusion is that green coffee can be washed. Short term exposure to
clean water does no harm provided the coffee is roasted within a few hours.
I did not do a comparison roast, this was just a feasibility test. But the
cup quality strikes me as more "smooth" than any roast I have made in my two
years as a homeroaster. This suggests the possibility of improving or
modifying coffees by washing.
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2) From: Don Staricka
Very interesting. I'll have to try this. Perhaps certain compounds leached 
out as the water was absorbed. Two hours is plenty long enough for that to 
occur. There is no doubt in my mind that coffee exposed to moisture for a 
long period of time would be adversely affected because of mold and other 
microbial pests. That is clearly not an issue here, however. I've never 
heard of anyone deliberately roasting water-saturated coffee before. You 
may be on to something.
Don
At 09:31 AM 3/7/02 -0500, you wrote:
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3) From: Henry C. Davis
Great, now I have to decide if I am going to wash my coffee before I roast
it :-)
Actually, it sounds like the real rule should be never get the green coffee
wet and let it sit around, but if it gets detritus in it you can wash it and
get a slightly different, but not unpleasant flavor....
I found the Jampit to be pretty smooth (without washing) as long as it rests
a bit (24-36hours). I guess now I will roast some, and then the next day,
wash another batch, roast it, and then brew them one right after the other
to compare. My wife tends to be adverse to some of the sharper edges on the
flavor of bright beans. Maybe this technique will fix that for her on some
varieties.
Did it roast faster, slower or the same with all that extra water?

4) From: Ken Mary
It is possible that most of the "extra" water evaporated in the 2 hours 
drying. I did not have my thermocouple in this popper, so no temp records.
The first crack sounded normal, actually there may have been fewer pops. The
roast time matched one of a different (unwashed) coffee a few days ago.
I will be doing some more washes on different coffees, keeping better
records and comparison cupping with unwashed.
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5) From: Gary Zimmerman
Hey Ken, great work!  Thanks - interesting.  True spirit of an explorer and 
questionner.
-- garyZ
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6) From: Ed Needham
Interesting.  I've always wondered about the nasties beans pick up in the
local washwater and in the open weave burlap bags thrown into containers and
dropped into the hold of a ship.  Since coffee beans are really just seeds,
I didn't see how an agitated wash and a well ventilated, controlled drying
would hurt the beans.
I am thinking that what you are calling chaff may be the silverskin that is
supposed to be removed in the processing, and I can only assume that
removing more of this would result in a better cup.  Wow, this is exciting!
Regards,
Ed Needham
ed

7) From: lists
When I was a Peace Corps Volunteer in Ethiopia, part for our daily coffee
ritual included washing the green beans prior to roasting.  The beans were
immersed in room tempature water.  The beans were then agitated and rubbed
between the palms of the hands.  The were then  rinsed and roasted.  It
never hurt!

8) From: Ken Mary
Call it what you want, this is the same stuff that comes off in roasting. 
Prior to this roast, I could see that most of the silverskin was removed,
leaving some bits stuck to maybe 5 to 10 beans. After the initial shake
following the soak, I noticed the skins floating around, so I made the extra
effort to wash off as much as possible. During the roast there were only a
few flakes of chaff blown out. No chaff was visible on any roasted bean
except that which occurs in the center.
I do not believe it was the silverskin removal that affected the flavor,
though some people may be sensitive to its taste.
I am wondering how much, if any, caffeine was removed in the soak. The
sweetness is still there, and the complexity after aging. The overall
impression is that of smoothness, so much so that it seems like nothing, not
even the water, touches the tongue, only flavors. It is an odd feeling to
me. Also the flavors are "delayed", blending into the aftertaste, which is
pleasant and longlasting.
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9) From: Tom & Maria
GREEN COFFEE IS A DRIED SEED . IT WILL SOAK UP WATER LIKE A SPONGE 
AND THAT WILL IMMEDIATELY AFFECT THE PHYSICAL NATURE OF THE SEED, AND 
WILL CHANGE THE CHEMICAL PROPERTIES OF THE ROAST...
DON'T WASH IT!
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            Sweet Maria's Home Coffee Roasting  -  Tom & Maria
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10) From: Simpson
Hi, Tom-
I just did this:
20.1 grams of Colombian San Augustin -Santa Isabella 100% Typica immersed
and agitated for 60 seconds in filtered tap water. Removed from water and
patted dry. 'Wet' weight was 20.4 grams, or and increase of .3 gram or
1.5%. If you left the coffee in for any time I suspect you would ruin it,
but a quick wash followed by roasting (otherwise mildew could set in)
shouldn't be TOO much of a problem, particularly if the alternative is
tossing a roast's worth of coffee. What have you got to lose with those
choices? BTW this was using a very accurate jeweler's scale.
Ted
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On 3/8/2002 at 10:28 AM Tom & Maria wrote:
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11) From: Ken Mary
I will post future studies in alt.coffee.
There is no need to wash or pretreat any of SM's coffees including the Java
Jampit. I am sorry if I gave that impression.
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12) From: Ed Needham
Heck Tom, we might have to experiment with pounds and pounds of green beans
to test this little theory. $$$$$$$
Regards,
Ed Needham
ed


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