All,
Sorry about the very long post, and about the technical stuff
no answers in here, only questions that probably belong in a more advanced brewing thread. Admittedly, a lot of the stuff in here is somewhat theoretical. And, all beer has tannins in it
all beer has some tannin from both hops and barley.
I think the question is whether the beer has tannins that are excessive to an individuals taste buds. I very much enjoy very bitter strong dark roasted coffee
others that work with me cannot stand the bitterness and strength, so they dilute it (I cry just a little when I see them do it)
. Just making a point about individual tastes
where is the individual's cutoff for too strong, versus just strong enough, versus too weak in flavors we find appealing and/or repulsive??
Revvy gives the facts...and the main objective idea to not make things too complicated:rockin:. I guarantee you that 300 years ago, experienced brewers in Germany were making great beer without checking pH
but I also can guarantee you that now, nearly every one of them do. Is the beer any better now than it was then
I dunno.
How many beginning home brewers actually check the pH of their wort? My guess is few until they have numerous batches under their belt - if my own approach to brewing for the first couple of years is any indication...I never checked my pH.
Was my pH too high and hence would extract more tannins if I squeeze too much and crush too finely (BTW, what is "too fine" to a beginning brewer in an uncontrolled kitchen environment...and not a large well controlled microbrewery)? Was the combination of pH and temperature enough to extract more tannin-derived flavors from the grain than what I personally enjoy? I don't know, because I never checked the pH of my steeping water with grains...I am guessing that many (most) beginning extract brewers that use steeping grains do not check the pH. Thus, split-batch experimentation is the answer if you are not prepared to delve deeply into the question just yet.
Tannin extraction is a time-dependent phenomenon, and a function of pH, temperature, crushed hull size (affecting surface area and hull density), water chemistry, solute volume...etc; there are multiple interlacing extraction/solubility curves associated with this problem...how do you deal with all of this as a beginning brewer? Answer: Follow a simple but incomplete rule when in doubt, don't squeeze.
For many beginning brewers, pH (and terms like "tannin" or "polyphenol" or "oxidizable polyphenols") is a "black box" and the squeeze or don't squeeze issue is real. So, understanding the gross/global difference between the effects of "to squeeze or not to squeeze" may make a difference in the flavor of your beer. Run the experiment and decide for yourself
I would like to see the results of a bunch of different beginner brewers experiments regarding this issue
I throw down the gauntlet
I triple-dog-dare all of you
. Have fun with it.
I can tell you that I have done the batch splitting squeeze/dont squeeze experiment, and I noticed a difference in the flavor profile of my beer
However, I readily admit this was not an unbiased blind scientific study, as I was actually looking for the differences. Maybe I simply found what I was looking for because I was convinced it was there
(this is a well established phenomenon associated with experimentation in general).
Experienced brewers should immediately realize the "never boil your grains" rule is BS on some level...as Revvy pointed out, decoction is proof in itself. But, experienced brewers know the real deal with at least some of the trade-offs involved in certain procedures. So, vorlauf, pH check, temperature range, stopping sparge when SG drops to 1.008 - 1.012, rapid wort cooling...all of this is standard practice for many experienced brewers to address astringency-causing tannins...but the squeeze/don't squeeze issue is an issue of the beginning beer brewer.
By the way, if we are supposed to stop sparging when the SG reaches 1.008-1.012, wouldnt squeezing the grain bed (as suggested in the linked threads), negate this procedure? Just another indication of conflicting ideas with no resolution?
My guess is that the "rule of thumb" don't squeeze your grains arose because of the pH issue - most new brewers don't check pH, or dont always enact other important procedures meant to reduce the final ppm of astringency-producing categories of polyphenols. Thus, the "don't squeeze" idea may have originated due to the fact that trying to explain the effects of pH and tannin extraction is simply too complex for new brewers (and let's face it...it would make an already intimidating process even more intimidating).
Sugars are much more soluble than complex oligomeric polyphenols that contribute to astringency
sugars will leave the grain much more quickly
squeezing the grain to remove sugars is not necessary
but squeezing will remove the water that is left soaked up into the grain hulls
water that may have a high concentration of partially soluble tannins. Those additional tannins will get into the wort
whether they are still in the wort after boiling and rapid cooling
is another question. If they do remain in the cooled wort - whether a brewer can taste the difference in their beer or not, may be an individual-level determination.
Revvy, your response in post #22 (
https://www.homebrewtalk.com/f39/squeezing-grain-bag-bad-175179/index3.html) suggests the problem
there are too many variables to actually know the accuracy of the information. BIAB website cites Dan Walker as the source
where did he get the information? I dont doubt his expertise in brewing, but where did he get the original information?
This whole issue smacks of many I have seen before
the results of single experiment in a controlled laboratory are interpreted to apply across a broad spectrum of environmental conditions. One/two well respected person/people suggests a conclusion to the issue at hand, and everyone else adopts the suggestion as fact. This is a common occurrence in science research. I have no idea from where the original source(s) of squeeze/dont squeeze hails.
I am not saying either conclusion is wrong
I am suggesting that there is not enough evidence to draw a certain conclusion. I dont know that I agree that this is a dead-horse issue mercilessly beat into the ground.
I have not seen curves describing the temperature/pH relationship
and the additional effects of pressure on the system. Some proteins that are in meta-stable conformations can be easily denatured by slight increases in pressure
is this effect apparent with tannin oligomerization/extraction also??? I have no answers for this, only questions. I am not pretending to know all about this
I have many, many questions also. I probably know just enough to ask strange questions.
A quick perusal of Secrets from the Master Brewers Higgins, Kilgore, Hertlein, will show that even the Masters dont always agree on cause/effect, and/or best practice procedures. One brewer's squeeze of trash, may be another brewer's squeeze of treasure.
Any comments on all of this from anyone else?
Cheers,
PikledBill