The first victim in my possibly statistically insignificant, and admittedly
somewhat non-rigorous brewing temperature test was the Melitta Clarity drip
coffeemaker.
The second victim, tested a little over an hour ago as I write this, is the
Presto "Scandinavian-design" programmable automatic drip coffeemaker. This
one claims to have three heating elements, one for the water heater, one for
the warmer plate, and an auxiliary one higher up in the plumbing path to
ensure that the brew temperature will be closer to the top end of the
optimal brewing temperature.
When I removed the Clarity from the counter and held it upside down to get
all that residual water out of the plumbing, my glue job to reattach that
broken foot under the water tank end of the machine gave it up and that
plastic foot hit the floor. Maybe I'll try Super Glue or Crazy Glue or
something similar to that on it next time. Gluing plastic to plastic is
usually tricky, since we don't always know the exact chemical composition of
the two plastics being joined.

I uaed the same gear and the same basic method to test the Presto. The
water tank was filled to the maximum amount it can comfortably hold of water
straight from my coldwater kitchen faucet. The thermometer said the
temperature of that water in the tank was 76.1 degrees Fahrenheit. The air
temperature in the room within aprox. 1 foot, (30 centimeters) of the
coffeemaker was 78.1 degrees Fahrenheit.

The ground coffee, which was cooler than the water, having been in the
freezer before being ground, was 57.5 degrees Fahrenheit.

The first drops of water hit the coffee about 16 seconds or so into the
brewing, as measured by the countup timer on the "stopwtch" function of the
digital watch. Since I was holding the thermometer positioned in the filter
basket throughout the brewing, with one hand, at least one second ellapsed
between the time I hit the brew button on the Presto and the stopwatch
function on the watch. Throughout the test, when the watch announced the
ellapsed time, at one second intervals up to ten seconds, ten second
intervals up to one minute, one minute intervals up to five minutes, and
five-minute intervals after five minutes, I could ellicit the spoken reading
from the thermometer almost immediately. Other times, probably reflect at
least a one-second actual time difference. Note, I did say I'm not claiming
this to be laboratory-science-rigorous by any means. Exact repeatability
from test to test probably won't happen spot-on, but I believe it is close
enough to give a reasonable real-world picture of what is happening in the
brew basket regarding temperature. One would expect the first few spurts of
wter to be cooler, and that the temperature of the saturated coffee and
water mixture in the basket would rise, hopefully fairly rapidly, toward
that ideal brewing temperature range as the brew cycle progresses.

The tip of the thermometer's probe was down inside the filter basket,
submerged in the coffee but not touching the very bottom of the filter cone
throughout the brewing time. A couple of minutes after brewing stopped and
after allowing some time for water to finish dripping out of the basket into
the carafe, I swung the filter basket out from under the drip spouts, and
positioned the Presto's narrow spout so I could place the probe down into
the carafe to get a temp reading of the coffee in the carafe, while still on
the warmer plate after brewing stopped, but before turning off the warmer
plate.

Here are the times, each on a line, followed by the temperature reading, on
a Fahrenheit scale. For comparison purposes, 100 dg. C. is 212 dg. F. 95
dg. C. is 203 dg. F. 90 dg. C. is 194 dg. F. 85 dg. C. is 185 dg. F. 80
dg. C. is 176 dg. F. 10 dg. C. is 50 dg. F. 15 dg. C. is 59 dg. F. 20 dg.
C. is 68 dg. F. 25 dg. C. is 77 dg. F.

10 seconds, 57.5
15 seconds, water drips,
20 seconds 58.6
30 seconds, 133.8
40 seconds, 151.5
50 seconds, 157.5
1 minute, 170.1
1 minute 9 seconds, 173.4
1 minute 21 seconds, 180.8
1 minute 35 seconds, 183.8
1 minute 47 seconds, 185.5
2 minutes, 192.1
2 minutes 10 seconds, 191
2 minutes 22 seconds, 194.6
2 minutes 33 seconds, 195.4
2 minutes 46 seconds, 203
3 minutes, 204.4
3 minutes 12 seconds, 204.2
3 minutes 23 seconds, 204.7
3 minutes 33 seconds, 204.7
3 minutes 47 seconds, 205
3 minutes 58 seconds, 205.1
4 minutes 10 seconds, 205.2
4 minutes 21 seconds, 199.5
4 minutes 34 seconds, 195.5
4 minutes 43 seconds, 194.1
4 minutes 56 seconds, 198.4
5 minutes 10 seconds, 199.3
5 minutes 13 seconds, 201.4
5 minutes 22 seconds, 201.3
5 minutes 29 seconds, 201.2
5 minutes 37 seconds, 201.6
5 minutes 47 seconds 201.6
5 minutes 56 seconds, 202.1
6 minutes 8 seconds, 202.8
6 minutes 15 seconds, 203
6 minutes 22 seconds, 203.9
6 minutes 29 seconds, 204.1
6 minutes 36 seconds, 204.6
6 minutes 42 seconds, 204.6
At 6 minutes 30 seconds, increased sputtering noises signals that we're
nearing the end of the tank. The electronics may be getting a bit hot
despite a protective heat-resistant lid cover under the electronics housing
of the thermometer. Several pressings of the talk button on the thermometer
do not ellicit a spoken reading.
6 minutes 33 seconds,
6 minutes 50 seconds
7 minutes, heavy slurping
7 minutes 13 seconds, 206.1 the water slurp is louder than the thermometer.
7 minutes 34 seconds, 202.9
8 minutes 20 seconds, switch clicks, pumping stops, no announced reading
8 minutes 45 seconds, 203.1
9 minutes, 203 degrees Fahrenheit
9 minutes 24 seconds, 202.4
9 minutes 39 seconds, 202.1

Transfer thermometer from brewing basket to carafe:
11 minutes, 182.3 degrees Fahrenheit
11 minutes 8 seconds, 182.4
11 minutes 26 seconds, 182.1
13 minutes 12 seconds, 179.3
13 minutes 35 seconds, 179.7
13 minutes 47 seconds, 179.5
14 minutes 2 seconds, 179.2
14 minutes 14 seconds, 178.9
15 minutes, 178.5
15 minutes 12 seconds, 178.2 degrees Fahrenheit.

That temperature dip between four-ish and five-ish minutes was interesting
and unexpected. Based on these two tests, the brewing temperature of the
Presto ramped up much sooner and more rapidly than it did with the Clarity,
and the optimal brewing temp between 90 and 95 dg. C. 194 and 203 degrees F.
was maintained over a considerably greater percentage of the total brewing
time.

With both machines, despite differences in carafe shape and size, I found
the drop from brew temp inside the basket during brewing to carafe temp with
a minute or three after brewing stopped to be quite significant, over 20
degrees Fahrenheit with both machines, over 25 degrees with the Presto, even
though the presto's warmer plate may be a couple degrees hotter than that of
the Clarity, despite the larger diameter of the warmer plate surface in the
Clarity.

Somebody posted fairly recently that he thought his Presto brewed hotter
than his clarity. My test would appear to confirm that observation to be
true.

My only possible explanation for that near 8 degree temperature dip in the
Presto's test profile may be that the auxiliary heating element must shut
off briefly during the brewing cycle to prevent it from bringing the brewing
temperature up to the boiling point, which is generally considered to be an
undesirable occurrance when brewing coffee, regardless of the brewing
method.

If you forget and leave the Presto turned on after brewing, the machine,
including its warming plate, will be shut off after two hours. With the
Clarity, remember to throw that two-pole switch. It will stay on until you
turn it off or unplug it.

Last Friday afternoon, I had brewed a fresh pot in the Clarity and then left
with somebody else to do some shopping, and was gone about two hours,
leaving the clarity turned on, keeping the coffee cooking in the carafe.

I checked the mailbox on the way back to the apartment after that little
trip and this thermometer was there, having arrived that afternoon. My
first test of it was to get an air temperature reading, and then I submerged
its probe into the Clarity's carafe, and figured the thermometer had
stabilized on a constant reading when I got three consecutive readings that
were the same. It reported that the Clarity was holding the coffee at a
temperature of 175.6 degrees Fahrenheit, just a couple degrees or so cooler
than the reading I got in the carafe very shortly after brewing when I ran
that brewing temperature test a couple days ago on the Clarity.

Brent Reynolds, Atlanta, GA USA
Email: Phone: 1-404-814-0768

| all that residual water out of the plumbing, my glue job to reattach that
| broken foot under the water tank end of the machine gave it up and that
| plastic foot hit the floor.

Try a PVC plumbing solvent adhesive (from the plumbing section of your
hardware store). Make sure there isn't a layer of another glue dried on the
surface to be glued.

| brew basket regarding temperature. One would expect the first few spurts of
| wter to be cooler, and that the temperature of the saturated coffee and
| water mixture in the basket would rise, hopefully fairly rapidly, toward
| that ideal brewing temperature range as the brew cycle progresses.

On some drip makers, temp can be made more uniform by preceding the brew by
a 'blank' brew (no coffee in the filter).

How did the coffee taste?

- David R.
--
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