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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
		Digest Janitor: pbabcock at hbd.org


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Contents:
  flow meters ("eric")
  Stuck fermentation vs. incomplete conversion? ("Ian Watson")
  flow meters and pedantic esoterica (ALAN K MEEKER)
  Of sight glasses and water filtration ("Mike Sharp")
  Throw away the sight glass (Thomas Rohner)
  Re: Flow Meters (John Schnupp)
  Drucker and Measurement (leavitdg)
  Measuring fermentation progress (Matt)
  Lagering a Duvel clone? ("Brian Schar")


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Date: Mon, 19 Dec 2005 21:38:51 -0700
From: "eric" <zeee1 at nebonet.com>
Subject: flow meters

Hello all

  Wouldn't relative humidity and absolute pressure (altitude and/or
barometric pressure) affect vapor pressure?

Eric

Deweyville, UT
Standard disclaimer: I have been wrong before, and will be again...


From: "A.J deLange" <ajdel at cox.net>
Subject: Flow Meters

Mike Sharp is thinking along the same sort of lines as I am, apparently.
WRT water vapor:  knowing the temperature of the fermenting beer should
be sufficient as one can assume the vapor pressure of H2O in the
headspace would be the tabulated vapor pressure of water at that
temperature (the mole fraction of water in fermenting beer must be well
over 90%).






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Date: Mon, 19 Dec 2005 23:51:43 -0500
From: "Ian Watson" <realtor at niagara.com>
Subject: Stuck fermentation vs. incomplete conversion?

Hi All

I haven't posted in a long time, but I recently was hired as the assistant
brewer at a new craft brewery in my city and I have an opinion I would like
confirmed or countered by the membership.  The owner and I brewed a batch on
the 9th of December and for the last 4 days the sg has been 1.018.  In  the
past the beer SHOULD have been, by this time, in the 1.010 to 1.008 range.
The boss's opinion is that the yeast is to blame, since we harvest and
re-pitch the yeast from previous batches.  I think the reason is incomplete
conversion:  On brewing day, after a mere 35 minutes of mashing, we mashed
out, after I though I saw some signs in the iodine test of incomplete
conversion.  So I say that the reason the sg is at 1.018 is that there are
still starches in the beer keeping the sg at that level.  What do you all
think?  Thank you either way you vote :)

Ian




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Date: Tue, 20 Dec 2005 00:07:31 -0500
From: ALAN K MEEKER <ameeker at mail.jhmi.edu>
Subject: flow meters and pedantic esoterica

Regarding the use of gas flow meters to monitor
CO2 production, A potential concern I raised with Ken
about the presence of water vapor in the fermentation
output (besides the effect on accuracy) is that, since
these meters are designed for use with dry gas, might
the water vapor damage the meter mechanism over
time? Thanks to Ken for alerting us about the meters
for auction on eBay. Mine got sniped!

John Peed suggested that the more "esoteric" posts be
moved to the HBD Discussion forum where there would
be participation form those who are interested in these 
topics. If you've been reading the HBD for any length
of time you've seen these same types of discussions
come up over and over. That is, folks questioning the 
practical value of some highly detailed, technical posts
and suggestions that they be moved to other venues. 
I would just say two things here. First, that so long as 
there is plenty of room in the queue there's no need to 
move posts elsewhere. If people do a decent
job of titling their posts it's a simple matter to ignore
those topics or threads that one isn't interested in (the
good 'ol page down key). Second, don't misinterpret a 
lack of participation in a discussion with lack of interest.
I for one find many of the more 'esoteric' posts quite
interesting, but I often don't have the time (or the 
knowledge) to contribute to them while they are active.

Cheers

Alan Meeker
Baltimore, MD


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Date: Mon, 19 Dec 2005 23:30:39 -0800
From: "Mike Sharp" <rdcpro at hotmail.com>
Subject: Of sight glasses and water filtration

MARTIN AMMON is considering throwing away the sight glass

"I was thinking (and that's when I get into trouble), if there was a way of
measuring the pressure in a stainless steel tube (sealed on one end) the air
pressure would vary as the water or wort level rise's or falls. Taking this
measurement and converting it into volume of liquid in the tank. That's
about as far as I can go with it.  Just a plain Old Country boy  any
thoughts out there."

Well, the pressure will be only due to the height of the water in the
vessel, so you don't need to bother with the sealed tube--just measure the
tank at the bottom.  And the pressure will be measured in inches of
water--about 0-24 inches if you're using a half barrel keg.  Given that 33
feet is around 15 psi (yeah, 14.7, but I'm calling it 15), your pressure
gauge would need to measure between zero and 1 psi, with a resolution of,
say .02 psi to be able to gauge level to within an inch.  These are just
approximations, to get the overall scale of the thing.  To be accurate, and
to measure wort, you'd need to know the specific gravity, and then calculate
the height based on the pressure and the SG.  

Not that it's not possible--you can buy pressure transducers that will
measure in that range (their range is typically listed in inches of water).
I even have a mechanical Heise gauge that will measure 0-30 inches fairly
accurately, but it needs calibration every so often.  But then, I have a
hydraulic dead weight tester, though it's really more useful for higher
pressures.  

Some manufacturers of the strain guage-based pressure transducers claim
their products are pretty stable, and to be honest, I've considered doing
the same thing myself--for the HLT.  But I can calibrate the thing if I need
to, which does complicate the situation for those without access to
calibration equipment.  Of course, if you had a sight glass, you could
measure the height of the water, and calibrate it that way!  

One other thing, though.  It's very common to use a "bubbler" system to
measure water height when the water is dirty or otherwise difficult to deal
with (ie: sewage).  The bubbler works by slowly bubbling air into the water
at the bottom of the vessel.  IIRC, it's about 1 bubble per second or so.
Anyway, the air pressure required to get a bubble every second is very close
to the pressure of the fluid, but air is a lot easier to measure without
screwing up the pressure sensor.  This is often done in an open channel
(like a parshall flume) to measure the height of the water flowing through
the narrow part, from which you can infer the flow rate of the water.  It
sounds like a tortuous way to measure flow, but it doesn't clog, and it's
pretty reliable.

A sight glass is a *lot* simpler!  ;^)


Bob Pelletier asks about Water Filtration

"I just wanted to confirm that running the water through the [activated
carbon] filter is only going to take sediment and chlorine type odor/flavor
out of the water and not any of the beneficial minerals out. Am I correct?"

Yes, that's basically correct.  It will also take out other nasty things,
like organic solvents, etc. But there shouldn't be much of that in your
water.  Keep the flow rate very low, to be effective, and don't use the
water for makup without boiling it (AC filters have bacterial seeding
problems).

"If I want and analysis of out municipal water, the DPW has to send it free
of charge don't they?"

I don't know about that, but most of them publish it on their web site, and
in many areas (like where I used to live in California), they mail it out to
every customer once per year.  They won't do the analysis for you, they'll
give you the results of the analysis they already performed because someone
else made them do it.

One thing, sometimes if the water system is big, your water may actually
come from one or more different sources, and it's impossible to tell which
at any time, since the water can get blended.  This was the case in San Luis
Obispo, which isn't even all that big.  Their water came from Whale Rock
reservoir, Santa Margarita reservoir, a bunch of wells, and several other
minor sources.  You could guess to a certain extent where the water was
coming from (they'd pull less from Santa Margarita during the summer,
because they had to maintain flow in the Salinas river), but it's a
crapshoot.  I looked at their distribution system pretty closely at various
times (I was doing a lot of control systems work in those days), and it was
very hard to tell what you were getting.  Their reports just showed the
analyses of the sources.

Regards,
Mike Sharp

Kent, Washington
[1891.3, 294deg] AR


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Date: Tue, 20 Dec 2005 11:16:04 +0100
From: Thomas Rohner <t.rohner at bluewin.ch>
Subject: Throw away the sight glass

Hi Martin

First: It is possible, but a sight glass could be the smaller nuisance, 
compared to a highly precise pressure gauge.
It takes 10m (33ft) water height to produce 1 bar (14.5psi). Taking my 
50l (13gal) tank i have a height of 0.6m (2ft) or so. That gives me a 
pressure of 60mbar or 0.87psi when full. Now you probably want to know 
it in a litre or quart resolution. That would bring us to 1.2mbar or 
0.017 psi per litre. This is somehow in the range of a barometer, but 
you know how delicate these instruments are, at least the good ones.

I would suggest you put a tube as a sleeve around your glass and make a 
sight-slot. You can put the slot on the side, so it would even survive a 
"frontal attack". My favourite would be stainless, but for machinability 
you could as well take alu. It's also possible to build some sort of 
cage around your glass, if it's easier to build for you.

This would be my "keep it simple ...." approach. (i use a calibrated 
stick for it ;-)

Cheers  thomas



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Date: Tue, 20 Dec 2005 04:12:31 -0800 (PST)
From: John Schnupp <johnschnupp at yahoo.com>
Subject: Re: Flow Meters

I was typing a reply yesterday when my computer saw fit to send it into the
ether.  I'll try and remember what I wrote as best I can.

MFM/MFC's do use temperature delta to determine flow as previously stated.  A
MFM is simply a mas flow monitor and an MFC is a mass flow controller.  You can
use a MFC as a monitor if you give it a max setpoint so that the control valve
opens fully. I'm most familiar with MFC's and their use in gas delivery systems
for semiconductor processing.  I'll use the terms interchangeably (even though
technically they are different).

AJ asks if MFC's are calibrated with the gas they flow.  The answer is yes and
no.  It largely depends upon the gas.  It would be a high risk to use arsine
(toxic/poison) to calibrate a MFC.  In this case a gas with similar thermal
properties is used instead.  On non-toxic controllers the source gas is often
used.  The most common gas used it N2.  There are charts that list correction
factor for various gases v. N2.  

AJ also asks if an MFM is a detector.  No.  The MFM has nothing to detect the
gas, it simply measures flow.  

Most of the MFM/MFC's I've seen are analog output of 0-5vdc.  There are digital
MFC's that use serial communications but I really don't have much experience
with them.  In the end, even a digital MFM/MFC needs to get back to analog to
do the actual measurement and control.

Mike brings up a good point about water vapor.  However, it's almost like 6 of
one or a half dozen of the other.  If the CO2 is mixed with water vapor then it
is either measure the CO2 knowing that water vapor needs to be taken into
account or measure the water vapor and make assumptions about the CO2 being
produced.  I don't know about water vapor MFM/MFC's, there may be some
different construction to take into account the effects of water.  If that is
the case then measuring water vapor would probably be the better choice.  As
far as determining the moisture content, wouldn't a cheap hydrometer give a
rough indication?  

John Schnupp, N3CNL
(once in a) Blue Moon Hombrewery
[560.2, 68.6] Rennerian
Georgia, VT
95 XLH 1200



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Date: Tue, 20 Dec 2005 07:19:49 -0500
From: leavitdg at plattsburgh.edu
Subject: Drucker and Measurement

Steve,

 Here is another quote, in response to Drucker's ("Peter F.Drucker states, "If
you can't measure it - you can't manage it", and this applies as well to
fermentations as corporations.

 -S"):

"Not everything that counts can be counted,
and not everything that can be counted
counts"
Einstein

Happy Holidays, -S, and others on the HbD
Darrell
Plattsburgh,NY 44 41 58 N Latitude
               73 27 12 W Longitude

 [544.9 miles, 68.9]Apparent Rennerian






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Date: Tue, 20 Dec 2005 08:04:12 -0800 (PST)
From: Matt <baumssl27 at yahoo.com>
Subject: Measuring fermentation progress

Some people lament the fact that one of the best indicators of
fermentation progress (the mass of CO2 that has left the fermenter) is
prohibitively expensive to measure.  A scale with range sufficient to
handle the weight of a fermenter, and enough accuracy to say anything
useful, is presumably too expensive.

Is this really true?  What do we really need?

A 5 gallon batch of high-gravity 1.080 OG wort in a carboy might weigh
as much as 25 kg.  How accurate the scale needs to be depends on your
definition of "useful"--for +/- 1 SG point we need something like +/-10
grams accuracy.

I propose that anyone capable of building a 3-tier brewing system
(which apparently a lot of you are) is able to construct such a scale
without breaking the bank.  

Just make a large beam-balance scale, with your fermenter hanging off
of one side, and weights on the other.  Easier said than done?  Let's
get to the details:

One of those "Carboy Carrier" things made of nylon webbing should do
nicely to suspend the carboy from the beam, if you're the kind of crazy
SOB who must ferment in glass even if your fermenter will be hanging
from a homemade balance beam.  (Put a rubbermaid tub under the carboy,
and hang it about 2" high.)  On the other side, hang a bucket from
which you will remove weights to measure escaped C02 mass.  Caribiners
will make everything quick and easy.  Try to make the sack much further
from the fulcrum than the carboy, to increase accuracy and reduce the
amount of weights you have to find.

How do we make the beam?  Not sure, but I AM sure that friction is not
our friend.  Maybe the beam is made from three 2x6 wood beams laminated
together (or bolted through) to make a nominally 6x6 beam.  A 1" hole
is cut through the plies of this beam, and a piece of nicely deburred
thick-wall water pipe lines this hole.  The beam hangs from this hole
on a STRONG, SHORT, and SLIGHTLY UNDERSIZED axle (cold rolled steel)
held tightly by some structure made of our beloved angle iron or 4x4s
or whatever, and voila.

Weigh several hundred pennies and divide by several hundred.  There's
your fancy set of counterweights, which you use once you have used
things like old tires and broken clocks to get close.  Don't forget how
many pennies you've put in the sack because that would just be
infuriating.

Problem: the horizontal distance between the center of mass of the
carboy and the fulcrum cannot change by more than about 0.02% between
measurements, if we are to maintain accuracy.  Same for the
counterweights.  If the carboy is 2 feet out then this is only 5
thousandths of an inch.  But if the weights are not swinging, we really
only need to worry about motion of the points from which they hang, and
this seems managable.

Matt  



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Date: Tue, 20 Dec 2005 16:33:24 -0800
From: "Brian Schar" <schar at cardica.com>
Subject: Lagering a Duvel clone?

Searching the HBD archives, I 
noticed that many people will 
lager their Duvel clones for 
a couple of weeks, starting at 
a time about two weeks into 
the fermentation process.  I 
don't have a lagering fridge, 
and would prefer to bypass the 
lagering step, if I decide to 
make a nice Belgian Strong 
Ale.  Has anyone had any luck 
making a decent Duvel clone 
without lagering? 

Brian Schar
Menlo Park, CA




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