HomeRoast Digest

Topic: Vacuum brewing frustrations - filter (5 msgs / 98 lines)
1) From: Jenkins, Jon
This message is in MIME format. Since your mail reader does not understand
this format, some or all of this message may not be legible.
I have a Bodum brewer and been using it for 6 months and still never been
able to get it to work correctly using the bodum disc or the Cona glass
filter.  The only filter I can get to work is the Yama.  Every time I try
the Bodum or Cona, it takes about 10-15 minutes for the water to drain back
into the bottom globe (after steeping with the grounds).  I have tried many
different grinds (use a Zass mill) and still no success.  Right now my grind
is French press or larger.  I would really like to get the Cona filter
operational.  Could the manufacturing of the cona filter or the bodum globe
be off spec?   Any ideas as to what I may be doing wrong?  Thanks in advance

2) From: Gary Zimmerman
Make sure the seal is tight between the upper and lower chambers.  If 
you've tried coarser grinds with no success, you may be losing the vacuum 
that's required to draw the brewed coffee back down.
-- garyZ
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

3) From: Ted Kostek
I don't have any experience with vac brewers, but this isn't how I thought
they worked.  Seems like the lower chamber develops high pressure and forces
the water up.  When the lower chamber cools, the pressure drops and the
upper gets sucked back down.  If you lose the seal, the lower chamber would
drop to ambient pressure, and the fluid from the upper chamber would fall
into the lower chamber.
Or is there some kind of valve that requires a pressure differential?  Have
I got the principles wrong?
Ted Kostek
765 494 2146 (desk)
765 494 1489 (engine room)
765 494 0787 (fax)
"Always keep in mind that your own resolution to succeed is more important
than any other thing."  Abraham Lincoln
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

4) From: sho2go
You've got it right, but remember the filter requires the pressure/vacuum to
function.  If you lose the seal, (don't ask how I know) it will take a very
long time to drip down.  This is using a Yama with a med. grind; YMMV.
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

5) From: Gary Zimmerman
garyZ wrote:
Ted Kostek wrote:
Yes, this is the (partial) "vacuum".  I guess nit-pickers would say that 
"partial vacuum" is an oxymoron, like "partial virgin".
Well, you're right, but...  If there was a poor seal, the lower chamber 
might not develop the full pressure it otherwise would on warm-up, except 
that the pressure and the speed at which it is developed is still more than 
sufficient to drive the water up the tube, assuming a relatively small 
pressure seal leak.
For the reverse trip, though, the leak would be much more significant, 
because the water needs to be driven through the resistance of the ground 
coffee.  In this case, depending on how finely and evenly the coffee is 
ground, the resistance is probably close enough to matching the gravity 
driving the water down that, without the aid of the pressure differential, 
the coffee stalls in the top, dammed by the damn grounds.
With time, perhaps, the water would eventually make it's way down, 
depending on how packed the grounds are, but it's likely to be a long wait.
-- garyZ
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

HomeRoast Digest