[Homeroast] Vac. pot seal breaking problem

sci scizen at gmail.com
Sun Jun 6 22:45:11 CDT 2010

Thanks for all the tips on avoiding super heated boil overs. One would think
that some explanation of this phenomena would come with the unit, lawyers or
not.   I have used a modern Santos for years, and a glass rod Cory. I never
had the boil over with either one. Nor have I ever seen any pot or kettle do
this either on a gas stove. The Hario had not done it after a few uses,
until this one time. The spherical shape and the small opening may have
exacerbated it. It was perfectly clean, and the water was heating in a
perfectly calm state the whole time, until kabam. But I do think I was using
lower heat. Obviously the stars were in the wrong place that day and the
Force was out of balance.  Fortunately, I was not in the wrong place.

I put two tiny scratches in the bottom on personal advice from a vac. pot
expert who has a collection of dozens of  pots. He told me that was a way to
stop this from happening, creating nucleation sites. LOL, you never know
about the advice you get sometimes. The bubbles now nucleate around those
two scratches, but I do now put the top section in with the chain and that
helps too. Just saying this again--I've read lots of things about vac pots
over the years, and followed the advice and instructions from several good
sources, and nobody ever mentioned this as a possible problem.


Date: Sun, 06 Jun 2010 09:40:24 -0500
From: Rich <rich-mail at octoxol.com>
To: "A list to discuss home coffee roasting. There are rules for this
       list,   available at http://www.sweetmarias.com/maillistinfo.html"
       <homeroast at lists.sweetmariascoffee.com>
Subject: Re: [Homeroast] Vac. pot seal breaking problem
Message-ID: <4C0BB358.8070602 at octoxol.com>
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The glass rod does nothing to reduce the possibility of super heating.
Vibration does though so if the kitchen floor bounces like a old
trampoline that will solve the issue.  Also for the glass rod users, the
rate of heat application makes a difference on the ease of producing
superheat.  A very low heat rate will cause it much more often than a
rapid heat rate.  The dissolved gases come out of solution at about 160F
with a rapid heat application and this stirs teh mass of water.  A slow
application may allow the bulk of the water to reach 160+F with no
agitation and then all gases evolve instantaneously.

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