Does cloudy runoff during lauter affect fermentation and final flavor?

Brewing Processes
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TL;DR - I decoction mashed and this causes lots of extra proteins, which are typically left behind in the lauter, given a proper vorlauf and lauter routine. However, my routine didn’t go as planned and about 2/5 of my fermenter tank wort consists of a lot of extra proteins and grain debris, which make the beer cloudy as all hell. My question is how do these extra particles affect fermentation and final flavor? Please try to keep conversation focused on the fermentation effects and less on the sparge/vorlauf/lauter routine. Also I would prefer scientific answers with maybe some sources from where you got the information. Qualitative experience is valuable, but I’m a bit more interested in the why than the how (if there turns out to be any impact on fermentation).

Yesterday I brewed with the following lauter plan with a rectangular mash/lauter tun, which utilizes a kettle screen filter. The plan was taken from Greg Noonan’s book called “New Brewing Lager Beer”. A similar plan is also listed on “How to Brew” by John Palmer.

  1. After 10 minutes of resting at mash-out (168F), vorlauf until wort runs clear, but never let wort volume in mash/lauter fall below a half inch above top of grain bed.

  2. Keep sparge water maintained in separate cooler at 175F during entire sparging process. Use a small pot to pull away sparge water from cooler and add to mash/lauter tun.

  3. Put runoff in kettle and immediately bring kettle wort to boil. Meanwhile, fill a pot with a small portion of sparge water. Simultaneously pour the sparge water over grain bed and lauter wort from mash/lauter turn, ensuring that you never let the wort fall below half inch above the grain bed.

  4. When all sparge water is used up from small pot, turn off mash/lauter tun spigot and put all runoff into kettle, which is boiling. Fill small pot again with new sparge water and repeat steps 3 and 4, until all sparge water is used up.

When I attempted to execute this plan, I succeeded on step 1. Having never vorlaufed before, I was quite amazed at the difference between extremely cloudy wort for the first runnings and crystal clear wort for the fourth runnings.

Unfortunately, the lauter rate (flow of wort out of mash/lauter tun) was too fast during step 1 and I think that compacted the grain bed and caused a stuck sparge. At the time, I didn’t know this info and thought my situation was hopeless, so I just scrapped the lauter plan entirely, threw the entire sparge volume in and continuously mixed the grain bed, so as to prevent a stuck sparge. However, my wort was extremely extremely cloudy, probably enhanced by the fact that I used a decoction mash procedure (this results in lots of extra proteins).

Anyway, after I boiled and cooled the wort, I attempted to whirlpool and let rest for 10 minutes to see if I could isolate those cloudy protein particles and grain debris. The whirlpool turned out to be totally futile because there was so much protein/debris trub, that the cloudiness took up an entire 2 gallons of the bottom of the kettle. I decided to take volume over wort quality, and I put a decent amount of the protein sludge into the fermenter.

So how does addition of the protein and grain debris trub into the fermenter affect fermentation and the final flavor? I know that no hop trub got into the fermenter, so the question is specific about protein/debris trub. If there is an impact, why does it happen? Why do the protein and grain debris affect the yeast?

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Plenty of people swear by brew in a bag, which creates a crazy cloudy wort. So, based on that, I don’t think it would affect the final flava flave.

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I would not expect to see any problems from protein making its way into the fermentor. Most will settle out and you can fine and/or cold crash to get rid of the rest.

I’ve never read anything that asserted protein affects fermentation or that it has a significant affect on flavor at the levels typical to beer.

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Grain debris as you call it can result in tannin extraction through the boil.  If the grain debris is husks.  If it is merely fine particulate (like flour) from the crush being too fine, you are probably ok.  It sounds like the latter based on the stuck sparge you encountered.  FWIW check out

http://dennybrew.com

For batch sparring explanations.  Denny stirs before runoff and then vorlaufs each time he runs off.

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Having made many test batches with BIAB (squeezing, no squeezing, recirc, no recirc, etc) I will not disagree that it works, HOWEVER. I had all my test batches scored (BJCP judges) and they all scored ~7-9 points lower than the same beer brewed traditionally. Just an FYI.

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That backs up my experience as well.

I know a lot of BIABers, especially on other forums, are always swearing that it’s the new “holy grail” method of brewing and that it’s pointless to upgrade to a traditional three-vessel system.

I always seem to find some taste difference as well. However, it’s slight, and I’m sure OP’s beer will be fine.

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I think there is a flavor difference with BIAB as well. I’m not sure it is from proteins, as OP has inquired about, as much as it is all that starch and husk material getting into the boil. To that end, this other matter may have an effect on OP’s beer.

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So I found a couple paragraphs in Noonan’s book that has the answer I’m looking for:

“The purpose of sparging/filter is to rinse the soluble extract free from the malt husks and to trap insoluble, poorly modified starch, protein, lipids, and silicates within the husks. Without adequate filtering, extract is lost, while the mash runoff is clouded by starch, proteins, tannins, and husk particles. This produces beer likely to be cloudy, astringent, and unstable.”

“The degree of clarity that should be obtained in the runoff is a matter of debate. A lot of draff carried into the kettle is a recipe for astringent beer, but a small amount may improve trub coagulation. The majority of brewers recycle until the runoff is no longer heavily clouded.”

I assume that he is talking less about the impact of the “draff” on the yeast, and more about the impact of the flavor of the “draff” itself. However, my hopes are that the majority of this shit just settles to the bottom and doesn’t get into the final beer when you rack to secondary.

Anyway, I have about 3 weeks of fermenting, 6 weeks of lagering, and 2 weeks of carbonating…so I’ll update the thread with the results. And then I’ll likely brew the same recipe again and if I don’t mess up the sparge, I’ll see if I can note a difference in flavor. I kind of doubt that it will really impact the flavor of the beer. In a couple weeks, I’ll update the thread with a picture of the settled trub so you can see how severe it is.

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This is runoff from a 60%pils, 30%wheat, lager. I like to keep it clean, and my beer thanks me for it  :wink: