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Topic: Moka pots & burning coffee? (12 msgs / 243 lines)
1) From: TFisher511
I have heard several times how you can burn coffee in a Moka pot but am not 
sure I understand how. Is it really that much different from a vacuum brewer 
in ease of burning coffee?
I would think you would need to leave the Moka pot on the burner long enough 
to boil all the water out of the bottom. It would then probably melt the 
gasket between the top and the  bottom and get the top part of the pot hot 
enough to burn the puck and the coffee up north.
I suppose I could try it with my > "Cherie" but I'm just not quite that 
<Snip>
Terry F
joshm writes:
<Snip>

2) From: jim gundlach
On Sunday, October 27, 2002, at 04:22 AM, TFisher511 wrote:
<Snip>
Burn is not quite the right word.  Coffee extracted with water above 
200 F extracts undesirables from the grounds and gives it what is 
called the "burnt" taste.  Anything that uses steam pressure to push 
water through a puck of coffee, moka pots and steam toys,  will expose 
the grounds to temperatures well above the 200 degrees F and the coffee 
simply does not taste good.  I have found that a moka pot works well at 
about 7,500 ft elevation and I attribute that to the lower temperature 
at which water boils way up there, 198 F. The main purpose of pump 
driven espresso machines is to use a thermostat to determine when the 
temperature is right to allow a pump to force the 195 to 198 or so 
degree F water through the coffee.   Temperature surfing is the process 
of using what manual control we have over the espresso machines to try 
to get water at a perfect temperature to the puck and overcome some of 
the limitations of the automatic controls in our machines.
Vac pots use steam to push the water up to the brewing pot but the 
water that gets to the coffee is well below boiling which allows the 
vac pot to make a "unburnt" coffee.
Jim Gundlach
roasting over pecan wood fires
in La Place, Alabama
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3) From: TFisher511
Jim,
The extraction at too high water temperature is the only thing that made 
sense about burning coffee in a Moka pot short of a meltdown. I had not 
considered that part of the process and that is a very good point. That would 
seem to insinuate that Moka pot coffee brewed at under 7500 feet would 
probably have that too high water temp characteristic.
I don't know. The Moka is an interesting little device but it is not my 
favorite extraction method considering the fooling around, the cleanup and 
the flavor.
Terry F
jimgundlach writes:
<Snip>

4) From: jim gundlach
Myron,
    See comments below:
On Sunday, October 27, 2002, at 08:04 AM, Myron Joshua wrote:
<Snip>
  If you open the top and watch the pot operate you should see a smooth 
dark liquid without bubbles at first.  This is when you have water 
without steam pushed through the puck.  As the process goes on, you 
will see bubbles added, this means that the water is too hot and 
quality will degrade.  If you don't stop the process you will finally 
see steam shooting through with small droplets of coffee spraying 
around.
<Snip>
That is why yours has the pressure valve.  It is a safety device, not 
something that improves the quality of the coffee.
<Snip>
Just the opposite, the higher the pressure the higher the temperature 
the more bitter the cup.
<Snip>
The 4 cup model probably gets hotter and stays hot longer than the 2 
cup model.  You probably will not be able to make as good a coffee with 
the 4 cup model.  This is the reason you do not see ten shot group 
heads on espresso machines.
Jim Gundlach
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5) From: Myron Joshua
Thanks for the explanation Jim.
But isn't it true that a Moka pot also has steam collect in the bottom
chamber that Pushes WATER and NOT STEAM through the grinds?
Once this water leaves the pressurized chamber the water might turn to steam
(while it is going through the grinds??) and this may be a dangerous
situation. Perhaps the extra weighted piece that sits on the orifice of the
Moka pot stem on the Brikka System prevents this from happening and that is
why it gives a better (and not bitter) cup.
Best,
Myron
"Trying his darnest to get as good cup out of the 4 cup brikka as he does
out of the 2 cup model!"

6) From: jim gundlach
On Sunday, October 27, 2002, at 07:34 AM, TFisher511 wrote:
<Snip>
I am not sure where the threshold would be, I've only tried it at 325 
and 7500 feet.  The one brewed at 7500 feet was quite good, the ones 
brewed at 325 feet were only drinkable until I tried my first one from 
a pump machine.  Someone else said they got good results at about 3000 
feet.
Jim Gundlach
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7) From: Myron Joshua
Jim wrote:
<Snip>
This is why I always stop the procedure before all the water goes through
the stem. I usually pour off before the bubbly stuff comes through. I have
tasted what continues to flow after i pour off and it is definitely very
inferior.
The Brikka System includes a weight on top of the stem that casues the
pressure to be a bit higher and effects water flow. It seems it holds the
water back and then lets it come out more rapidly. Perhaps this way  more
water flows  through the grinds before the boiling water has a chance to
reach them.
I swear that this system does produce something very Crema like-oils that
stick solidly to the cup. This could be covering the burnt taste.
You are right that this added weight would also cause the water to be a
higher temperature. But the outcome is a smoother cup.
<Snip>
Yep, i thought of this as well. Some have suggested preheating the water so
that the Moka pot has less chance to heat up. I also thought of using a
higher flame to speed up the process.

8) From: Rick Farris
Jim wrote:
<Snip>
However, if you poke around on the coffeetec website I posted earlier, you
will find a 6-group machine!
-- Rick
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9) From: Jim Garlits
I saw that machine!  Do you know how much foot traffic it would take to keep
it running at full cap?  You'd need an aircraft hangar for the lines.  The
boiler was a beaut, though.  Quite a conversation piece, but overkill in my
estimation.
Jim G.

10) From: jim gundlach
On Sunday, October 27, 2002, at 04:22 PM, Rick Farris wrote:
<Snip>
Exactly, six heads that will produce a double shot each.  When you want 
to produce more you have to go to more groups rather than bigger 
groups.  There are groups that take filters that hold the coffee for  
ten or twelve shot pulls.
Jim Gundlach
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11) From: Angelo
Judging from the responses, I think I am one of the few people who has 
actually measured the temp of the coffee as it comes out of the spout of a 
Moka pot. It is well below boiling. The principle of the moka pot is not 
that much different than that of the vac pot, it's just in reverse: where 
the vac pot pulls the water through the grounds via pressure, the Moka pot 
pushes the water through.
Many people have expressed concern because the water bubbles in the top of 
the Vac pot, calling it "boiling". That has been shown to be a 
misconception. The water expands and rises way before it boils.The same 
thing happens in the Moka pot.
  I would suggest, however, that you not use too high a flame under the pot 
when you use it, and to cut the flame just as the coffee is beginning to 
slow. Practice will show you the sweet spot...
The use of a thermometer should put all your concerns to rest. Remember, 
the Moka pot is rumored to be the preferred method of brewing, not only in 
Italy, but in most of Europe and South America, so it shouldn't be too much 
of a risk to try it.:-)...
Ciao,
Angelo
<Snip>
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12) From: James Gundlach
On Monday, October 28, 2002, at 02:01 PM, Angelo wrote:
<Snip>
I don't think there is sufficient pre-boiling thermal expansion in the 
volume of water that we put in these small pots to brew any coffee.  I 
just put a measurement vial in the microwave with 45 ml of 58F water.  
I put it into the microwave and brought it up to 205F and at most it 
increased in volume by 0.5 ml.   And, most of that was probably due to 
the evaporated bubbles along the side of the vial.
In a moka pot, the first water may lose some of its heat before it 
makes it to the top but there is not enough pre-boiling thermal 
expansion to even get the coffee wet in a moka pot.
Jim Gundlach
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