HomeRoast Digest


Topic: eVac infusion time adjust >was Re: +Failure to grok (52 lines)
1) From: Mike McGinness
First I plea ignorance of 'grok', or I'm too short (as in over my head:-)
Here's a cut & paste from the archives of a post I made in February:
First it must be understood how the Bodum eSantos 3000 & Starbucks Utopia
"time" the infusion. They don't. The design is such the the heater element
in the base of the pot is at an angle higher towards the handle (call it the
Front) and lower at the back. As the water is heated it is pushed North
(into the infusion chamber.) When almost all the water is North and air is
pushed North causing bubbling mixing of the water ground mixture infusion is
considered begun for this discussion. On a LEVEL surface infusion/bubbling
begins while the entire heater element is still wet. As the small amount of
water remaining down South evaporates the heating element begins to dry
beginning towards the elevated Front. When approximately 1" of the element
is dry it shuts off and presto, the infused coffee heads South.
I ran 6 tests all with no grounds. The first 3 control runs I varied the
amount of water at 30, 40 & 50oz. Each time the infusion "time" averaged
1min 7sec. not varying by more than 5 sec. Next I elevated the back of the
base 2mm (the width of a Clean Time coin I had in my pocket.) This in effect
lowered the Front reducing the angle of the heater element. Hence the end
water stays on it longer. I ran 3 more runs with the same varied amounts of
water. Infusion "time" now averaged 1min 50sec, a 45sec increase.
I just ran a 7th test elevating the back 4mm with 40oz water. Infusion
"time" 2min 18sec.
A clear pattern is evident and I believe useful.
Conclusion: Many roasters are subject to voltage and temperature variations.
Now we have an  Electric Vacuum Brewer subject to LEVELING and maybe also
subject to voltage variations. If a lower voltage caused the remaining water
to evaporate slower it would then infuse longer... So to manually control
your infusion "Jack It Up" and manually turn it off when you want it to end!
NOTE: I did not check the level of my counter!!! I did keep the Utopia in
the same spot for each test.
End cut & paste.
I put two 1/4" self-stick rubber feet on the back of the base to permanently
raise it. This gives me an average 2min infusion which works great with a
grind about half way between drip and espresso (same grind I use for 2min
French Press infusing...)
From: "jim jordan" 
<Snip>
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