Why isn't an Iodine test the "defacto" standard for mash time?

[menschmaschine]

If as the Cargill literature states

Not that it makes a big difference, but this wasn't published literature. It was a post on ProBrewer.com. I recall reading this a year or so ago. I have to disagree with the two premises in that post. One is that long conversion rests are bad; and two that foam formed during the entire brewing process is lost foam.

I just read Brewing Science and Practice, the chapter(s) on mashing and not once does Briggs indicate long conversion time as having a negative influence on wort quality. In fact, he states that typical conversion times are 1.25 to 2.5 hours. He does discuss lipids and polyphenols, but conversion times do not seem to affect the levels of these (or their byproducts) in wort production. I think it's also worth noting, in regards to the Cargill post, that there is a big difference between laboratory mash conversion times and brewhouse conversion times. He indicates that most North American 2-row converts in 5-6 minutes, but this is likely a reference to a fine-grind laboratory mash which is indicated on the malt analysis.

As for the lost foam, I can't find information either way regarding foam constituents coming out of solution and staying out of solution, therefore becoming lost foam. However, Briggs does mention that beer should be handled carefully in a section on foam stability. But I have a hard time believing, for instance, that foam produced by wort aeration is lost foam. At any rate, there could be some merit to it, but he makes it sound like if I shake aerate my wort, I'm going to have no foam formation or stability, which isn't the case.

 

[ClaudiusB]

As for the lost foam, I can't find information either way regarding foam constituents coming out of solution and staying out of solution, therefore becoming lost foam.

Not much info

Chris Colby writes:
Lastly, homebrewers who keg their beer should be aware that foam positive molecules can get “used up” when foam is created. Thus, if you shake your keg to carbonate it, you may be dipping into your pool of foam makers for your beer.
Chris Colby: Getting good beer foam


Cheers,
ClaudiusB

 

[scinerd3000]

Good info Kai, You are a great attribute to this community! Maybe I'll pick a bottle of iodine. you just put a drop on say a paper plate, then a drop of wort onto that?

Not much info

saw this a few pages back-
Careful with paper plates because they can cause a false postive iodine test. Many of the paper plates have starches in them and will cause the wort and the plate to show up purple....do yourself a favor and either add it to a testube or ceramic. Cheers

 

[pjj2ba]

I guess I'm leaning towards believing foam proteins can be "used up". I'm not sure what reactions are occurring during head formation. Is it simply hydrogen bonds forming between proteins as the beeer is poured? This then wouldn't get used up, but then what is to prevent the H-bonding to occur in the bottle before opening it. To me this then suggests that some other reactions are occurring with the porteins not serving as just a catalyst, but as a reactant in the reaction, and thus are modified somehow during head formation and don't go back to their original state for more head forming action.

I guess a way to test this would be to pour a beer and then bubble it with CO2 and see if you don't loose any head. Or maybe if someone here has a carbonator cap they could pour some beer into a 2 liter bottle, cap it and shake it to get a nice head. Then put it on the carbonator cap and re-carbonate it, then shake and see what happens. Repeat if neccessary. I think best would be to use a beer from a keg that has been well equilibrated with one's system so the beer in the 2 liter bottle could be returned to the same carbonation level.

 

[SpanishCastleAle]

Hmmm, I'm about to float a keg that I've already bottled from. I suppose I could shake that keg a bunch, let it stabilize/settle for a few days, then bottle a few and let them rest for a week or so and then compare to the 'original' bottles. The little bit of yeast/trub sludge in the bottom of the keg would be put back into suspension when I shake it up though. Would this be an effective test? Not as controlled as I'd like.

 

[menschmaschine]

Hmmm, I'm about to float a keg that I've already bottled from. I suppose I could shake that keg a bunch, let it stabilize/settle for a few days, then bottle a few and let them rest for a week or so and then compare to the 'original' bottles. The little bit of yeast/trub sludge in the bottom of the keg would be put back into suspension when I shake it up though. Would this be an effective test? Not as controlled as I'd like.

Hey, can't hurt to try. I'd be interested in your results. I think pjjtba hit the nail on head... what is happening chemically? Are bonds formed/broken?... can they be broken/re-formed when the foam settles back into the beer? How does ETOH concentration and pH affect it?... etc.

So, the question is, what is responsible for foam besides CO2? If it's largely Protein Z and LTP1, what is happening as they come out of solution and can anything help them to go back into solution?

 

[SpanishCastleAle]

So, the question is, what is responsible for foam besides CO2? If it's largely Protein Z and LTP1, what is happening as they come out of solution and can anything help them to go back into solution?

It appears even just the LTP1 protein can be altered to make it more foam-stable.

From that BYO/Chris Colby article:

The foam formed from beer-foam-isolated LTP1 was not as stable as foam from the entire low molecular weight fraction. And interestingly, the beer foam formed from LTP1 extracted from unmalted barley was very unstable. The inference here was that something in the malting or brewing process alters LTP1 to make it more able to generate foam.

I also wondered if the pH or alcohol was inhibiting the LTP1 from returning to it's orig foam-positive state. Since we often see Duvel as the case example I'm gonna guess it's not the alcohol.

 

[Kaiser]

Kai... do you mind if I copy your post and paste it to my club e-mail site?

No, go ahead

Kai

 

[Kaiser]

I’m finally getting around to catching up with my old replies.

Yes, longer mashing will extract more polyphenols and other undesirable compounds from the husks. But so does decoction mashing and many swear by it for certain styles. To circumvent or allevate this problem a small number of breweries does “endosperm mashing” where they separate endosperm and husks after milling, mash only the endosperm and add the husks at mash-out before they start lautering.

But most breweries don’t bother with that complication as it doesn’t seem to make much of a difference anyway. Besides that there may also be positive aspects to longer rests. Better attenuation is one and another one that I find references to is a long rest at 160F for better foam and body. Brewing is full of compromises and as a brewer we have to strike the balance as we see fit.

SpanischCastleAle, If you had done the fast ferment test you would know by now what fermentability your mash produced.

As for foam, it is held together by proteins and hop acids. All of which are hydrophilic in nature and lower the surface tension of the liquid. Because they hate water (hydrophobic) they tend to migrate into the foam and act to stabilize it. Ethanol and lipids (fats) can get into the way of these compounds bonding with each other and have a foam negative effect. I know that my Bocks don’t form a dense long lasting head but my Pilsners can get heads that seem as stable as meringues. This is at least anecdotal evidence for the effects of hops and ethanol on the foam.

I too would be interested in seeing an experiment that demonstrates that foaming potential can be used up.

Kai

 

[menschmaschine]

Maybe this is a question that attempts to oversimplify, but if foam constituents come out of solution and stay out of solution, wouldn't a beer have haze or sediment once the foam subsides?

 

[SpanishCastleAle]

OK Kaiser you've convinced me..I'm gonna try doing FFTs...esp on my lagers.

Maybe if I bottled a few from the same keg and left extra head space. Shake the hell out of a couple; several times over the course of one evening, and don't shake the others and then wait a few days for everything to settle/equalize. Compare.

 

[pjj2ba]

I just set up some starters and it occurred to me that this might be a good way to test the lifespan of foam positive proteins. Next time I save some leftover wort - which I typically then autoclave at work (unfortunately I just inoculated the ones that had been sitting on my bench for the past 6 weeks), then I can just give it a good shake every day and see if I get foam. I can then repeat ad nausem and see what happens. This way I don't need to worry about any carbonation issue. Although I'm fairly sure the yeast make a difference in head though as I have numerous kegs of anecdotal information that say that the longer the aging, the better the head (My pipeline is sufficient such that I don't drink green beer). Regardless, this would be a good way to test wort proteins and foam.

 

[PhlyanPan]

I think I'm going to stop reading Kai's posts.

Every time I do it simply reminds me how little I know about brewing...and that really it's simply a combination of dumb luck and the magic of yeast that's making these delicious brews.

 

[SpanishCastleAle]

In any case, I'm brewing a Sticke Alt today and I'm gonna try a very short version of the temp-ramp mash mentioned at the end of that thread (posted by Larry). Dough-in to rest @ 144 for 5 min, ramp to 158 over 20 min, rest @ 158 for 5 min, test for conversion, mash-out @ 168. It's mostly a 1:1 mix of Pils:Light Munich with a little Caramunich and a tiny bit of Carafa Special II.

FWIW, I just racked this Sticke Alt and it went from 1.064 to 1.015 using White Labs European Ale yeast (WL site says 65%-70% att. but I've never gotten anywhere near that low attenuation with it). It was a decent amount I think, it was a 3 month old ~30mL 'cake' of washed yeast in a 3 qt. starter, decanted. I expected a higher FG. Sample tastes a bit more bitter/hoppy than I expected.

EDIT: I should be brewing another Enkle tomorrow and will try this mash schedule again and will do an FFT this time.