How to Cold Crash Your Beer?

by Karl S Updated on May 1, 2020

After going through the rigorous processes of malting, lautering, fermenting, filtering, and conditioning, there are times when you are still not satisfied with your brew.

In a situation like this, we often find ourselves indulged in various refining processes aimed at improving the colour and flavour of the Beer. Out of the many methods that we do, we often fail to consider the clarity of the brew as a parameter to judge our Beer.

One such process which helps increase the clarity and transparency of your is Cold-Crashing. 

Cold crashing is a simple technique that ensures that your beers and wines have crystal clear solutions, just like the ones we see on billboards and commercials. 

Though simple, the cold crashing process is all about the right temperature and timing. 

But, before moving forward, it is essential to understand that why we should include cold crashing in our refining process. To help you master the process of cold-crashing and to enhance your beer brewing experience, we list down some tips and hacks to help you get the best Beer ever. 

Why is Cold Crashing a Beer so Important?

The primary objective of Cold Crashing is to release of aggregation of yeast that forms, resulting in a much more transparent and colloidal suspension free solution. 

Put in simple terms, cold crashing is a process of quick cooling that results in a beer that is crystal clear.

This quick cooling process causes the yeast aggregations and other particle suspensions to collect together as a single entity of protein. After getting collected to a separate protein entity, the accumulated mass starts drawing down to the bottom of the container, and gradually out of the suspension.

The above process then results in a much clearer and satisfying beer brew.

How To Catalyze The Cold Crashing Of A Beer?

Now, just like most chemical reactions in nature, this process can also be improved and optimized to desired results using additives or catalysts as we call them in Chemistry.

One such agent is Irish Moss, or what is also know as Whirlfloc. Irish Moss can help to release the congestion faster. In addition to the above, Irish moss also possesses some anti-viral and anti-bacterial properties. 

Another such additive is Gelatin. Gelatin is known for its unique amino acid properties and holds anti-bacterial and anti-viral properties. 

The addition of Gelatin in the post-fermentation process coupled with cold crashing does wonders for your Beer. The simple method is as follows –

  • Boil a cup of water,
  • Whisk the right amount of Gelatin
  • Add the fermenter. 

Results are immediate and efficient, so much so that you can see the clear Beer within 24 hours instead of the typical three days it would require to cold crashing.

The Flavour Benefits of Cold Crashing.

Even though there is not enough substance to prove if the cold crashing process alters the taste and flavour of the brew, there is a hypothesis that says – The characters in the cold crashed Beer is more stable and consistent. The rational reason to support this hypothesis is that the particulate matter is eradicated and removed from the Beer, thus resulting in a consistent flavour throughout.

What is the perfect temperature for a cold crashing process?

In simple terms, cold crashing is the process of chilling down your beer to 0.5 C or 33 F in a short period. To carry out this process, you can put the fermenting container in a controlled freezer

The above procedure is also possible in a regular fridge or freezer, but it will, more often than not, fail to give the ideal final product.

When To Start Cold Crashing A Beer?

Though very simple, the cold crashing process is very much dependent on the timing of the process. It is essential to ensure that the fermentation process has taken its course completely. If the fermentation is not complete, it can result in the yeast not being able to function due to the low temperatures. This will then further lead to primal sugars being left in the beer, thus resulting in inconsistent off flavour.

In addition to the above, compounds like Dimethyl Sulphide, which are subdued by the action of the yeasts, leads to undesirable flavors in the brew.

Ensuring that your beer has completed its fermentation process will lead to a better taste. You can check the progress of the fermentation process using a hydrometer. When confirmed, cold crash the beer.

The Maths Behind The Cold Crashing Process

Cold cruising, as mentioned, is the process of drastically bringing down the temperature in a very short amount of time. This sudden change in temperature gives rise to a chain reaction caused by a survival reaction in yeast. The particles which do not gel together or consolidated to one more prominent protein coagulate fall to the bottom of the vessel. 

At this particular moment, the Stokes Law comes into action. The stokes law helps us calculate the settling velocity of small spheres in a liquid medium. This law states that this settling velocity is proportional to the radius of the spheres it forms. 

The larger the formation of the spherical colloid, the faster it will go down to the bottom of the vessel. 

Now, as we discussed before, Irish moss acts as a catalyst to optimize the cold crashing process; the Irish moss is primarily a seaweed. The primary constituent of this seaweed is k -carrageenan. The structure of this compound resembles a helix, which, when heated, unwinds itself. 

This compound then attracts the positively charged particles, and after the temperature cools down, regains its origin helix shape, thus falling out of the suspension and leading to a clear transparent brew.


Many factors help determine the quality of your beer. Many of us, for instance, tend to overlook is the appearance of our beer. 

Now, cold crashing is a relatively simple and easy way to improve the overall clarity and consistency of beer.

Even though it’s the effect on the flavour of the beer is negligible, this process makes your beer look better, thus improving your beer brewing and further, beer-drinking experience.