---

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


***************************************************************
       THIS YEAR'S HOME BREW DIGEST BROUGHT TO YOU BY: 

                     Your Business Name Here
    Visit http://hbd.org "Sponsor the HBD"  to find out how!
			 
    Support those who support you! Visit our sponsor's site!
********** Also visit http://hbd.org/hbdsponsors.html *********


Contents:
  re: Esters/4VG/N2 ("steve.alexander")
  Nitrogen ("A.J deLange")
  4vg (clove) production ("Spencer W. Thomas")
  Re: Stella Artois ("Doug Hurst")
  Effect of dissolved extract on volume (rather geeky) ("Bill Pierce")


* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*           The HBD Logo Store is now open!             *
*            http://www.hbd.org/store.html              *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*  Suppport this service: http://hbd.org/donate.shtml   *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*   Beer is our obsession and we're late for therapy!   *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Send articles for __publication_only__ to post@hbd.org

If your e-mail account is being deleted, please unsubscribe first!!

To SUBSCRIBE or UNSUBSCRIBE send an e-mail message with the word
  "subscribe" or "unsubscribe" to request@hbd.org FROM THE E-MAIL
  ACCOUNT YOU WISH TO HAVE SUBSCRIBED OR UNSUBSCRIBED!!!**
IF YOU HAVE SPAM-PROOFED your e-mail address, you cannot subscribe to
  the digest as we cannot reach you. We will not correct your address
  for the automation - that's your job.

HAVING TROUBLE posting, subscribing or unsusubscribing? See the HBD FAQ at
http://hbd.org.

LOOKING TO BUY OR SELL USED EQUIPMENT? Please do not post about it here. Go
instead to http://homebrewfleamarket.com and post a free ad there.

The HBD is a copyrighted document. The compilation is copyright 
  HBD.ORG. Individual postings are copyright by their authors. ASK 
  before reproducing and you'll rarely have trouble. Digest content 
  cannot be reproduced by any means for sale or profit.

More information is available by sending the word "info" to 
req@hbd.org or read the HBD FAQ at http://hbd.org.

JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning,
                  and Spencer Thomas



----------------------------------------------------------------------


Date: Tue, 25 Sep 2007 04:43:34 -0400
From: "steve.alexander" <-s at roadrunner.com>
Subject: re: Esters/4VG/N2

Richard Lynch asks,


> > -S, You when you wrote about the downside of
> >underpitching, you mentioned that there are other ways
> >to produce flavors from a yeast, that we must "torture
> >our little buddies". Could you (or anyone) elaborate
> >please?
> >  
> >
>   

You can find all the detail in the archive, but the short course is ....
Yeast produce a majority of their esters right at the point where they get
the signal they are running out of a some required nutrient.  The yeast
metabolism shifts from growth to maintenance fermentation and some
storage carbo accumulation.  The half-built fatty (short chain) acids the
 yeast were constructing for growth/reproduction are not only
unnecessary but toxic. Perhaps for this reason the yeast produce a burst
of enzymes just as growth ceases  which, together with some energy
and the abundant alcohols convert the fatty acids to esters,  The esters
are more soluble and less toxic.  The same enzymes that esterify these
short & medium chain fatty acids(carboxylic acids) will also esterify
very short carboxylic acids like acetic acid.in beer together with the
various fusels and so produce the aromatic esters in beer.

Yeast produce some esters all along, but there is a big rise just as the
fermentation trails and yeast growth stops, but of course the ester
production spike requires that the yeast are producing fatty acids, that
they have energy and that the normal levels of fusels and acetic are
available.  Adding fatty acids to the wort (or including excess trub)
means the yeast don't need to produce FAs so far less esters.  If
carbohydrates (fermentable sugars) are the first growth requirement
that yeast run out of then they may be energy deficient and produce
less esters. If you underpitch then the pitched yeast - even if well
aerated - will not have sufficient sterol and UFA to divide & grow
until the end - so they will produce abundant esters (but maybe also
not finish dry)..  If you under oxygenate at a normal pitch rate, then
again the yeast run out of sterols and so produce esters, but it's more
likely IMO that the larger yeast mass will finish the sugars even if
slowly.  If you overoxygenate then you generally get less esters unless
you run out of amino acids needed to fuel growth.  The enzymes
involved are very temperature sensitive so if you arrange to have
the fermenter temp rise as the fermentation trails then you get
more esters and also a more rapid finish.  It's a rare event to have
insufficient fusels and simple carboxylic acids to drive the process.

Generally speaking the two most prominent cause of the cessation
of yeast growth (reproduction halts but fermentation continues)  in
malt-wort are lack of sterols (derived from oxygenating the yeast)
and lack of wort amino acids after the yeast have used these up.

So my opinion is that using clean wort (no trub) boosting the
mid-ferment temps and reducing aeration of a normal
amount of yeast is a better method for more esters than is
underpitched.  At least be very careful about the extent of
underpitching if you choose that approach.

Yeast varieties are quite variable in the specific esters they
produce and their ratios and amounts - so do select your yeast
for ester aromas.


> >I recently brewed a Hefeweizen using Wyeast 3068 and
> >am a little disappointed with the results.  It just
> >doesn't have much of the intense yeast-aroma and
> >flavor "kick" that says Hefeweizen.  I fermented
> >around 67F, pitched a quart of slurry from a
> >propagator pack.  I'm new at Hefewiezens, and would
> >love to be able to make a Paulaner clone, any pointers
> >would great, thanks!
> >  
> >
>   

67F is pretty cool if you want esters, and you want big esters in a
hefeweizen.  I'd readily pitch at that temp, but slowly plan the temp
rise to 75F or even 80F as the fermentation trails off, then back down.
The 4VG clove flavor is the result of a yeast metabolism of ferulic acid.
Wheat has more ferulic than barley and is released at or under low
saccharification temps in the mash.  I've heard reports that 4VG
production is also temp dependent (more at higher fermentation
temps) but that's uncertain. 4VG declines over a period of months
at beer storage temps so hefe's are usually best fresh.

Weizen yeasts seem to autolyze rather rapidly - so getting the beer
off the yeast within a couple days of the mark is important.

- --


> >Subject: Nitrogen in carbon dioxide cylindeers?
> >
>   
Although nitrogen is used in a mix when serving
certain beers like Guinness, the literature claims
that nitrogen destroys hop flavor in beer.  I find
this a bit surprising since nitrogen is so inert
but ....

 -S








Return to table of contents


Date: Tue, 25 Sep 2007 12:55:42 +0000
From: "A.J deLange" <ajdel at cox.net>
Subject: Nitrogen

The critical temperature of nitrogen is 126 K (about -147C) which means 
that at room temperature it cannot exist as a liquid no matter what the 
pressure so that consideration of vapor pressure does not apply. The 
good news is that the indicated pressure relative to the pressure when 
the bottle was full tells you how much remains. For example if 
originally filled to 14 MPa half the gas has been consumed when the 
gauge reads 7 MPa. The bad news is that one cannot get much into a small 
bottle because the compression ratio is approximately the ratio of the 
cylinder pressure to apmospheric pressure. 14 MPa (approximately 2000 
psig which is a typical fill level) is approximately 140 atmospheres so 
that  each cubic foot of bottle capacity holds approximately 140 cubic 
feet of gas at room temperature. A bottle of beer mix the size of the 
typical 5 pound CO2 bottle will thus push a keg or two of beer as 
opposed to dozens of kegs from the same size CO2 bottle.

As pointed out no-one pushes beer with straight nitrogen. The beer would 
be flat and unappetizing. What people do use is "beer mix" which is 
typically 60% CO2 and 40% nitrogen or "stout mix" which is 25% CO2 and 
75% nitrogen. In both cases the object is to have some CO2 dissolved in 
the beer but to use the pressure of the nitrogen to drive it through 
long lines and/or through the "sparkler" in a stout or ale faucet thus 
producing the creamy head which is a must for Irish Stout and a 
desirement for other ales. I serve some lagers on mix as well.

In the US (don't know about Oz) CO2 equipment and N2 equipment 
(regulators, hoses, connectors) are of different types specifically to 
prevent installation of one type of gas in a system intended for 
another). There is no fundamental reason that a CO2 bottle filled with 
nitrogen to below its working limits shouldn't be safe if allowance is 
made for pressure increase as temperature rises. In the US, however, a 
supplier would probably refuse to fill nitrogen (or any gas other than 
CO2) into a CO2 bottle. For starters his filler wouldn't match the CGA 
320 connector found on all CO3 bottles here.

Try a welding supply outfit. They should have CO2. In the states many of 
them have beer mix as well but it's expensive and it doesn't go far as I 
noted above.

A.J.


Return to table of contents


Date: Tue, 25 Sep 2007 10:54:39 -0400
From: "Spencer W. Thomas" <hbd at spencerwthomas.com>
Subject: 4vg (clove) production

The cloviest weizen I ever tasted was fermented at 62F according to the
(professional) brewer.  I forget now which yeast she used, but it was one of
the "usual suspects."  This beer had almost no banana and a huge clove
profile.  Personally, I liked it, but it was definitely outside the normal
weizen range.

Some others on this list may have tasted it -- it was brewed at Dragonmead
and was on tap during the MCAB judging that was held there a couple of years
ago.

=Spencer in Ann Arbor



Return to table of contents


Date: Tue, 25 Sep 2007 13:25:35 -0500
From: "Doug Hurst" <dougbeer2000 at gmail.com>
Subject: Re: Stella Artois

When I visited the brewery, there was a display with a sample of each
of the ingredients in the sterile brewhouse.  I can tell you to skip the
crystal malt, add some rice adjunct and use a Northern European, Danish,
or Carlsberg yeast strain.  I'd stick to Saaz but don't bitter or aroma as
highly as a Czech pils.  I don't think they're dosing with solid hops,
favoring the extracts instead.

Hope this helps,

Doug Hurst
Chicago, IL


Return to table of contents


Date: Tue, 25 Sep 2007 18:26:23 -0400
From: "Bill Pierce" <BillPierce at aol.com>
Subject: Effect of dissolved extract on volume (rather geeky)

I have a brewing spreadsheet, and occasionally I consider adding
another bell or whistle to its various sections.  This time I
thought it might be interesting to calculate the weight of the spent
grain, which led me to another issue altogether.

During mashing a significant portion of the grain is converted to
sugars that are dissolved in the runoff and ultimately boiled in the
kettle.  This reduces the weight of the grain, although not quite
equal to the added weight of the absorbed water in the mash (if you
do the mash you will confirm this).  Of course the extracted sugars
increase the weight of the runoff and the wort.  But they also have
an effect on volume.

As extract brewers, we probably encountered the fact that when we
dissolved the extract in the hot water there was an increase in
volume (adding to the risk of a boilover if the kettle is not large
enough).  In the case of liquid extract we may have attributed the
increase to the fact that LME is typically 20 percent water.  But
the phenomenon also occurs with DME, which has a very small moisture
content.

The amount of the increase is measurable.  While the formula is not
quite linear due to molecular interactions, the average figure I
found (I wish I could recall the source; it's lost to me now) for
the gravities typical of wort is that each pound of sucrose (or
other sugar) adds 9.48 US fluid ounces to the volume (61.4 ml for
each 100 grams, for the metrically inclined).

As an example, consider a standard 5 gallon extract batch with 6
lbs. of DME in 7 gallons (pre-boil) of water. With an extract
potential of 1.045, DME has 97.38 percent the extract value of
sucrose (extract potential 1.04621). In terms of extract points,
45/46.21=0.9738. Multiplied by the weight, that results in the
equivalent of 5.84 lbs. of sucrose (6*0.9738).

To determine the weight of the water, multiply the volume of 7
gallons by 8.32487 (the weight of 1 gallon of water at standard
temperature and pressure, according to a chemistry manual), for a
total of 58.27 lbs. Add the weight of the sucrose equivalent for a
total pre-boil weight of 64.11 lbs. (58.27+5.84). Calculate the
extract percentage by weight; the value is 9.11 degrees Plato
(5.84/64.11*100), or a specific gravity of 1.0364.

As for the volume, the additional 5.48 lbs. of extract will add
51.62 fluid oz. (5.48*9.42) or 0.403 gallon (51.62/128), resulting
in a total volume of 7.403 gallons (7+0.403), an increase in volume
of 5.76 percent (0.403/7*100).  If we check our math by calculating
the gravity using the traditional method of gravity points, we have
a specific gravity of 1.0364 (1+(6*45/7.403/1000)) or 9.11 degrees
Plato, the same value we calculated for the percentage of extract by
weight.

In addition to the dissolved extract increasing the pre-boil volume,
there is another implication for the all-grain brewer.  The usual
method of achieving the correct pre-boil volume is to calculate the
target and sparge the grain until it is reached.  It's possible (and
relatively common practice) merely to prepare enough hot sparge
water to ensure this occurs.  But some brewers (and much of the
brewing software out there) also calculate the total volume of water
needed for both mashing and sparging.

Now my question is whether the calculations and software account for
the increase in volume due to the dissolved extract.   So far as I
can tell, all of the brewing software water-needed calculators do
not.  If we use the above example of a target pre-boil volume of
7.403 gallons, the sparge water volume should be reduced by 0.403
gallon.  Otherwise, unless the brewer measures and monitors the
pre-boil volume, he or she is likely to be oversparging.

I'm wondering if there are any errors in my thinking and why the
software many of us use doesn't account for this factor.  While the
error isn't extreme, neither is it insignificant.

Brew on!

Bill Pierce
Cellar Door Homebrewery
Burlington, Ontario
BillPierce_(at)_aol.com



Return to table of contents

---