Beer Protein Stabilization

In the world of drinks, beer is largely a protein drink. It’s true. There is plenty of protein both in the grain, usually malted barley, and in the yeast that ferments it. That’s not to say that you can take beer as a main source of protein. Still, yay for high protein lovers!

But wait, beer protein stabilization is a real concern for brewers because, when not treated properly, those proteins can get out of control.

So, what do we do?

What Is Beer Protein?

First, it’s important to understand exactly what it is we are talking about.

When we make beer, we take a malted grain, which is to say a grain that has sprouted, or germinated, and then toasted. These grains are high in sugars and proteins, perfect for making beer.

We grind that malted grain down in order to expose all those sugars and proteins to the water we pour over it, and then we bring that water with the ground sugary grain to a high boil for around 60 minutes.

Then we cool down the wort, filter out the grain, and add yeast.

Now, as the yeast ferments, consuming the sugars in the wort and producing alcohol and carbon dioxide as waste products, the proteins from the grain and the yeast are interacting and creating their own byproducts.

The grain, the yeast, and the hops all contain proteins, polypeptides, and polyphenols, often in the form of tannins, which are the chemical components that create the beloved haze in hazy IPAs and crisp summer wheat beers.

We love haze, to a certain extent.

But unstable protein can create a bit of chaos.

Colloidal Stability

The haze in beer is what is known as colloids, or colloidal haze. Colloids are the combination of protein molecules and tannins forming large molecular aggregates, large enough for us to see with the naked eye.

In most cases, this is a good thing.

Colloidal haze is what gives IPA a thick, rich texture, the proteins give us mouthfeel, flavor, and aroma.

Indeed, beer without yeast and the fermentation process would taste dull and flat, just grain water.

We want alcohol and we want proteins.

But we want those proteins to be stable.

Without proper stabilization of beer proteins, we could end up with a gelatinous mess, too much haze, and an overpowering of the beer’s flavor and texture.

How to Ensure Beer Protein Stabilization

Thus, beer protein stabilization is an important part of the brewing process, and it is actually not a truly difficult one.

Beer Conditioning

First, it is critical to note that beer must be conditioned. Beer conditioning, when overlooked, can lead to either “green” beer, meaning beer that has not fully matured and may present either as dull and lifeless or with off flavors.

To condition beer, we allow the yeast cells to complete their job. You see, the first fermentation is only the beginning.

The first step in fermentation is the boil, long before we even add the yeast. We call this a hot break, which brings the proteins up to such a high temperature for long enough that they break down fully and will not come back together.

Once the wort has cooled and the yeast has been added, krausening is an excellent step in beer conditioning, allowing the yeast to foam and bubble, forming a thick crust on the top of the wort, which signals peak primary fermentation, and then the krausen will slowly dissipate, leaving you with flocculated yeast either on top of the beer or the bottom of the vessel.

Cold break after primary fermentation then allows the trub to be thickened up and removed, which will also filter out larger proteins and polyphenols that would form a too gelatinous haze in beer.

Do note that in removing these polyphenols, you are also potentially removing contributors to mouthfeel, flavor, and aroma, so cold break, and how cold you go, is optional and should be experimented with.

Secondary Fermentation

Now we move into secondary fermentation, which can include lagering, which brings the beer down to much cooler temperatures and allows the remaining yeast cells to do their final sweep.

During lagering, or even just a secondary fermentation at a warmer temperature, the yeast will continue to consume dead yeast cells and other larger fermentables in the beer, smoothing out flavor and aroma and stabilizing proteins.

Giving beer time to ferment a second time, either at colder temperatures for longer periods of time, or even in casks, will allow your proteins time to stabilize.

Then, you can clarify before bottling, canning, or kegging, if need be.

Clarification

After secondary fermentation, most yeast cells and larger molecules will collect at the bottom of your vessel and can be filtered out.

However, you can also add fining agents to speed up the sedimentation process or use a centrifuge to remove yeast and other solids.

Isinglass is the most popular fining agent used, which is a traditional ale clarifier. It is added after secondary fermentation and allowed to sit for 48 hours. The Isinglass will form clumps with the yeast, allowing for easier filtration.

The centrifuge is used either during beer transfer, between first and secondary fermentation, or after secondary fermentation to clarify beer after yeast sediment has been removed.

Stabilization Agents

Stabilization agents then are used typically only as a last resort and should not be relied on in lieu of any of the above processes.

The danger of relying on stabilization agents as a primary method for beer protein stabilization is interfering with natural mouthfeel, aroma, and texture you will get from beer than has been properly brewed.

Commonly used agents, also known as chillproofing agents because they aid in the stabilization of proteins while the beer sits on a cold shelf, are Proteolytic enzymes, tanning acid, Hydrolysable tannins, silica gels, bentonite, and Polyvinylpolypyrrolidone.

Each agent has its pros and cons and is worth experimenting with, but again only when necessary.

The goal of the brewing process is always going to be to create a beer that produces stable proteins and the haze, or lack thereof, that you desire, without the use of additional agents.

Cheers!

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Sources:

1. https://www.beer-brewing.com/beer_brewing/beer_brewing_conditioning/beer_stabilization.htm
2. https://www.brewersjournal.info/beer-colloidal-stability/

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