HomeRoast Digest

Topic: The fourth method is magic? (18 msgs / 367 lines)
1) From: Ken Mary
In my previous post of Sep 1, I described 3 methods of mixing hot water and
coffee for french press. I tried a fourth method as follows: In a glass
measuring cup, add the required quantity of water, then pour about half into
the press pot and heat both together in the microwave until boiling. Then
pour the hot water from the press pot into the measuring cup and continue
heating, while adding the ground coffee to the empty hot press pot. When the
measuring cup water begins to boil again, immediately pour rapidly into the
press pot but slow down when the foam reaches the top. And the foam *will*
reach the top. This method makes much more foam than any other that I have
tried, one actual measurement was 2 3/8 inches. This foam will quickly
reduce in volume, so when it reaches the top continue pouring slowly.
I cannot explain the huge quantity of foam, but slightly higher water
temperature may play a part. With no measurements to confirm it as yet, the
initial "boiling" may be a degassing effect. Years ago when I regularly
heated water in a mug for making tea, I noticed an initial boiling that
lasted for maybe ten seconds then a perfectly calm period for about 5
seconds followed by a more violent boiling. I assumed the initial boiling
was produced by degassing from the porous walls of the mug. The above
reheating may allow the water to finish degassing and approach the actual
boiling temperature. Also the walls of the measuring cup will be hotter
resulting in less heat loss.
Compared to the other 3 methods, there is a definite taste improvement. In
one or two brews I may have tasted what may be overextraction, but I am not
sure. In these brews I may have poured too soon and had too high a
temperature. More thorough study will be done over the next few weeks
including temperature measurements of the "boiling" water and the brew.
Ken Mary - Aromaroast - whirlyblade - decanter

2) From: Tom & Maria
I find that the when I added the water vigorously -quickly - it creates
more of a foamy head. All the old-stlye coffee stystems had aerators in the
nozles and even pouring water from 10-12 inches into something is going to
aerate it. I am wondering if microwaved water is less aerated. I am sure
boiling the water by any method  aerates it quite well, but I know a lot of
people who use the microwave never get water to the point it is vigorously
boiling. BTW a fresh drum roast (slower roast) will foam up more than an
air roast of the same freshness: air roasting releases more co2 in the
roast process than drum roasting. Your drum roasted coffee has more
residual co2 in it, at least for the first 24 hours after roasting at whcih
all the methods will have about the same co2 content...
                  "Great coffee comes from tiny roasters"
           Sweet Maria's Home Coffee Roasting  -  Tom & Maria

3) From: cationic
Boiling water actually removes the dissolved oxygen (and other gases)from
it. In general, the solubility of a gas in a liquid decreases as you raise
the temperature. Letting boiled water cool down (without stirring it) does
not fully restore the dissolved gases in it. You have to "aereate" it by
repeatedly pouring it from one container into another.
This topic brought back memories of my growing up in Mexico. As you probably
know, it is not advisable to drink water straight from the tap down there.
Before the advent of filters, we had to boil the water before we could drink
it. At home, we always had pots of boiling water on the stove. I remember
how foul that water tastes - if you don't re-aereate it. It only took a
couple of minutes to do so, and the difference was truly remarkable!

4) From: Mark

5) From: Hammonds, Derek
Um, just a question.  Is it OK to put the press pot into the microwave?  I
don't know about yours but mine (a Bodum) has a metal "holder" for the glass
caraffe.  I didn't think it was OK to put metal into a microwave...

6) From: James Winter
I'm no physicist, but I believe microwave ovens can heat water to a "boiling
point" temperature without actual boiling due to lack of thermal currents
that accompany other methods of heating water. Bubbles form around small
impurities in  water - usually the small amounts of air stirred into water
by these swirling thermal currents that can be seen in a stove top pot.
The microwave doesn't induce these thermal currents, so bubbles don't tend
to form, even if a liquid is at or even a bit above 212F.
When one adds impurities( i.e. coffee grounds - sorry for the blasphemy!)to
the microwaved water, the water suddenly has a nidus around which to
propagate bubbles - which are made all at once, creating the foamy effect.
I think.

7) From: Gary Zimmerman
James Winter wrote:
If you heat a mug of water, even to the boiling point (takes about 4-5 
minutes in my microwave) then take it out and wait until the bubbling 
stops, virtually ANYTHING you put in the water at that point will cause it 
to fizz and bubble like crazy.  A teabag, a spoon, anything.  Even just tap 
the mug or put it down on the counter rather abruptly.  I thought this was 
because the microwaves somehow supersaturated the water or something, but I 
have no idea really what the cause is.  Just noticed the effect 
consistently.  It's interesting, fun, and - if you're not expecting it - 
potentially dangerous.
-- garyZ

8) From: Michael Allen Smith
Am I the only one that is happy with good ole boiling water from a kettle?

9) From: Gary Zimmerman
-- garyZ
        & vacuum

10) From: Daniel Ho
hahahahaha....I was just thinking the same thing!
on 00/9/6 23:11, Michael Allen Smith at mas wrote:

11) From: Robert Cantor
kettle it is!    Microwaving a metal holder will cause the metal to get very
hot - well above the boiling point.  It may crack the glass, destroy the
plastic handle (even though it's thermoplastic) and melt your skin (4th
degree burns and skin grafts) if you're unfortunate enough to touch it.  And
the water may not even get to 100 degrees while the metal approaches 400 or
Microwave ovens have hot spots and cool spots, so the currents induced are
smaller than a range top where all the heat comes from the bottom.  Since
the temperature is non-uniform in microwaved water, you can see boiling
(steam production) but when you stir the water it may be cooler than you
expect (but still hot enough to burn you).
Bob C.

12) From: Robert Norton
There's a good chance that microwaved water is superheated and liable to
boil up violently with the least agitation. A number of people are severely
burned this way every year.

13) From: Dave Huddle
Yep.  Superheating is the problem with microwaved heated water.
In my years as a lab chemist, we ALWAYS added small boiling
chips/stones to liquids being boiled or distilled.   The rough surface
of the chips provided a place for bubbles to form so that boiling
proceeded smoothly, with out violent splashing.
On a related note - My wife reheated a cup of Sumatra Golden Pwani this
AM in the microwave and reported that it 'blew up' all over the
interior of the microwave.   (Cup didn't break, she wasn't injured.)
I have severly chastised her for such disrespectful treatment of the
fine coffee I serve her!
However, I shouldn't be to harsh, since she did buy me the Hearthware
Precision, a couple of grinders and an espresso machine.
Dave	Westerville, OH 	just 25 minutes from SweetMaria's

14) From: John & Carolyn Abbott
Most microwave ovens are equipped with a mixer or stirrer.  The oscillation
will provide even current to the bottom 70% of the cavity.  If you place the
container in the exact center you may get a slightly higher reading - but if
you place it about 1/3 of the way into the cavity you will always get the
same current for each power setting.
I'm not an expert but was the project manager on the first Litton Microwave

15) From: cationic
Yes. Liquids heated in a microwave may unexpectedly boil.
Consider the following safety warning from an Amana microwave oven
"Liquids heated in certain shaped containers (especially cylindrical-shaped
containers) may become overheated. The liquid may splash out with a loud
noise during or after heating or when adding ingredients (instant coffee,
etc.), resulting in harm to the oven and possible injury. In all containers,
for best results, stir the liquid several times before heating. Always stir
liquid several times between reheatings."

16) From: Don Staricka
The Golden Pwani is a natural low-grade rocket fuel. It was not the coffee 
that blew up but the vapor released during sublimation. There must have 
been some kind of spark in the oven's chamber. Never reheat Golden Pwani in 
a microwave. I'm surprised Tom didn't mention this to you. The Platinum 
Pwani is even worse. It contains an organic catalyst that triples the 
explosive power. Platinum Pwani can not legally be sold in the United 
States. The word "Pwani" is Indonesian for "kick in the head".
At 02:29 PM 9/7/00 -0400, you wrote:

17) From: Tom & Maria
I just wanted to say that this list is amazing: I learn A LOT here. I cant
believe how much expertise we have here. Lets write a book! (well ...
coordinating that might be the organizational disaster of the new
                  "Great coffee comes from tiny roasters"
           Sweet Maria's Home Coffee Roasting  -  Tom & Maria

18) From: Michael Rochman
Tom, was sitting here thinking about a FAQ for the list. Your idea of 
a book is even better. Some of these guys DO know a hell of a lot 
and the rest of us are learning fast.
The constant experimentation keeps things fresh and keeps us 
from becoming clones, as with many other hobbies.
And, the caliber of people involved is high..very high. 
I belong to ~many~ lists. Some quite large...receive at least 500 
emails per day. This is the only list to which I belong where there is 
no major bickering; where individuals can (and do) express 
themselves and disagree with each other in a most pleasant 
This is one fine group of people!
Thank you for bringing us together.
And, thank you for continuing to supply the best at very fair prices.
On 7 Sep 2000, at 20:42, Tom & Maria wrote:

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