Enzymes: Do they linger?

[TechFanMD]

When using enzymes on the cold side, do they linger on the equipment?

Basically, if you use enzymes such as glucoamylase on the cold side in a brut IPA or for other reasons, will they then linger on your equipment, or are they denatured/'killed' through use of Star-San? Are they simply rinsed away with a large enough volume of water through cleaning to be insignificant? ....or is there a concern that future batches may be 'contaminated' with enzymes and the result will be lower than planned gravities (and possible bottle bombs)?

 

[couchsending]

They linger for sure!

They denature at high heat so if you’re fermenting in stainless I’d recommend some boiling water in top of a solid cleaning with PBW.

 

[Vale71]

With proper cleaning you shouldn't have any residue capable of causing the slighest change in your wort composition. Unlike microbes enzymes cannot reproduce so while a microscopic microbial contamination might end up causing a full scale infection, undetectable enzyme residue won't really have any effect on your beer.

 

[TechFanMD]

With proper cleaning you shouldn't have any residue capable of causing the slighest change in your wort composition. Unlike microbes enzymes cannot reproduce so while a microscopic microbial contamination micht end up causing a full scale infection, undetectable enzyme residue won't really have any effect on your beer.

Thank you. That was my understanding but wanted to be sure.

 

[Vale71]

They denature at high heat so if you’re fermenting in stainless I’d recommend some boiling water in top of a solid cleaning with PBW.

Contrary to popular lore enzymes denature at lower temperatures as well, they just do it much more slowly. That's why diastatic power is an important paramenter when evaluating malt quality, especially if you're going to use large percentages of unmalted adjuncts. One might think that it is always possible to compensate for the reduced diastatic power of an adjunct-laden grist by increasing the saccharification step duration but that is not necessarily the case. It's basically a race condition between the enzymes being able to convert all the starch before they lose all enzymatic power and conversion essentially stops. Without going into details this has to do with the way hydration water interacts with their structure progressively damaging it and thus rendering them ineffective.
Long story short, the minuscule residue you might have left after a through cleaning is not really going to do much to your wort/beer before it moves on to greener pastures (or maybe greener mashes?? ).

 

[couchsending]

I don’t know. Was visiting a brewery this fall where I know the head brewer rather well. He’s been a head brewer for 30+ years, won tons of golds at GABF and WBC for multiple styles, Alpha King, mid size brewpub of the year, etc etc. It’s just him brewing with one assistant. Place is immaculate and he’s incredibly thorough in everything he does. Doesn’t strike me as someone to skimp on a CIP or cleaning process of any sort.

They had brewed a Brut IPA and added the enzyme to the FV. Said he was more thorough in cleaning that tank than he would be any other and the next batch in that tank exhibited the same attenuation with no enzymes and a fresh pitch of yeast from BSI.

I’ve also spoken to a head brewer at a large almost macro brewery who’s been using the same enzyme for more than 10+ years in Light beer production and he said he would never ever use it in the fermenter...

 

[Vale71]

The "would not use it in the fermenter" was probably due to the fact that their beer was not going to be pasteurized? If you don't pasteurize then having the enzymes stop at the desired FG becomes a bit trickier as you can only play around with enzyme dosage.

Your pro-brewer friends were just being a bit paranoid IMHO. Especially with commercial-sized tanks the amount of residue after a normal CIP cycle would be so small (I would guess it would be measured in picograms/liter?) that it would take years for those enzymes to have any noticeable effect. This would require the beer to be kept for this long and for the enzymes never to denature, which is just not the case. If you buy synthetic enzymes you'll notice that there's always a best-by date on the bottle and there is a reason for that. Enzymes are just not infinitely stable when hydrated.

 

[couchsending]

@Vale71 who do u work for?

 

[passedpawn]

I like vale's simple comment that after dilution due to cleaning, the amt of enzymes left would be insignificant (the solution to pollution is dilution ). Exactly!

But to answer the original question, acids at a very low pH will denature the enzymes. It's common to all proteins, where the bonds that hold them together solubilize and then permanently alter the protein structure. Well, at least that's what I've been told I don't have any idea what pH (low, or high) is required to denature glucoamylase, or if there is any other catalyst needed (e.g., temperature).

See this (my boy is a organic chemist and sent this to me): https://www.slideshare.net/priyankaflorina/denaturation-of-proteins

 

[isomerization]

Not all enzymes denature at low pH (see pepsin that is active in the stomach).

It’s also important to consider that a lot of enzymes will be able to refold after thermal denaturation and regain activity. I don’t know if this occurs with glucoamylase.

I would agree with very low odds of batch-to-batch contamination (at least at the homebrew scale), can’t recall comment about commercially scale.

EDIT: Here’s a paper on glucoamylase from Aspergillus which is commonly used in brewing:
https://umexpert.um.edu.my/file/publication/00007712_78557.pdf

Stable below pH 3 and up to 60C

 

[Vale71]

It’s also important to consider that a lot of enzymes will be able to refold after thermal denaturation and regain activity. I don’t know if this occurs with glucoamylase.

Fortunately they don't or every beer we brew would be a brut IPA. Glucoamylase is present in malt but is already denatured at gelatinization temperatures, making it ineffective in the mash. If they did become active again once wort is cooled we would all be getting out of this world attenuation values without the need for enzyme additions.

 

[Vale71]

@Vale71 who do u work for?

Why, you want to make me an offer I can't refuse?