Beer Clarity and Finings, Part 4

In the previous sections we discussed how to measure clarity, causes of poor clarity, proteins and tannins and how to control and improve beer clarity in the mash and the boil. Today we’re going to discuss fermentation finings and filtering your beer to improve clarity and reduce beer haze.

Lagering and Cold Crashing during Fermentation

When fermentation is complete, you may want to consider cold storing or cold crashing your beer. Lowering the temperature to near freezing will aid the precipitation of yeast, proteins and polyphenols. Also storing your beer cold is a great way to prepare it for filtering if desired.

Note that cold crashing (rapidly chilling the beer to near freezing) will kill off any remaining yeast, so you should not use this technique when bottling unless you are planning to pitch additional yeast when bottling. If you cold crash a beer you are bottling, and don’t add additional yeast to aid in carbonation you will get flat beer.

Fermentation Finings

A number of finings can also be used during fermentation. Most are added at the end of fermentation, a few days before bottling or kegging. This allows fermentation to complete, but gives the finings time to work and settle out some particulates.

• Gelatin — Available in the Jell-O section of the grocery store - in ‘unflavored’ packets. Prepare a packet in a pint of hot water, and then add it to your 5 gal (19 liter) batch a few days before bottling. Works on both proteins and tannins.

• Polyclar (PVPP) plastic — Polyclar is a polymer based powder that takes on a positive charge, and is effective at removing proteins, tannins and yeast. You can purchase it from most homebrew shops and should be used at a rate of about 1 tablespoon per 5 gallons (19 liters).

• Silica Gels — Includes a number of new brand name products. These gels are effective at binding proteins in particular, though they can affect flavor and foam retention if used in excess. These are added at a rate of 5-10 grams per 5 gal (19 liter) batch.

• Isinglass — A thin, fiberglass-like substance that is derived from fish bladders and has been used for a long time in brewing. It is effective for removing yeast cells and proteins, and also removes some lipids which can actually improve foam stability. Some people who have very strong allergies to shellfish can have a reaction to this substance though, so some care must be taken.

• Papain — Used more extensively in wine making, this is one of the first finings used commercially for clarity. It has fallen out of use by most professional brewers, however, as it has a negative impact on foam stability.

Filtering Your Beer

Obviously commercial breweries cannot afford to have their beer sitting for weeks and months while waiting for it to clear. Instead they often use filtration to filter out unwanted yeast along with larger proteins and tannins, so the beer can be sold much more quickly. Filtering also improves flavor stability, which is important for commercial brewers who want the same flavor from start to finish.

If possible you should chill your beer first as this maximizes the effectiveness of filtering. Most home brewers use an inline filter between two kegs, and simply filter while transferring the beer from one to the other. A two stage filter works best, with the first stage being a coarse 5 micron filter to remove large particles and yeasts, and a second 0.5 micron filter to remove the smaller particles. A two stage setup like this is much less likely to clog, and maximizes the life of both filters (most filters are disposable).

Storage and Stability

Once your beer is kegged or bottled, you need to worry about storing it properly. The most important thing you can do (assuming carbonation is complete) is to cold store your beer. Cold storage will improve clarity of your finished beer and will also maintain its stability for the longest period.

In particular you want to avoid cycling your beer from warm to cold. Cycling temperatures will definitely make your clarity problems worse, and is a major contributor to both chill haze and permanent haze.

Oxygen also plays a significant role in preserving clarity and stability in your beer. Even a small amount of oxygen left in the beer will act as a catalyst for permanent haze formation. Oxygen added when transferring wort or bottling/kegging is the largest risk, so extra care must be taken to avoid splashing or adding oxygen at any point after fermentation has started.

Summary

To summarize some of the key points regarding clarity: Choose low protein malts, mash and sparge at a low pH (5.2 is ideal), don’t oversparge or disturb the grain bed when sparging. Boil for a full 90 minutes, and add a boil fining such as whilfloc. Chill your wort as quickly as possible after the boil to get a good cold break, and consider cold crashing your beer once fermentation is done. Use finings before bottling and kegging, and consider filtering your beer. Avoid introducing oxygen at all costs, and cold store your beer.

If you do all of these things you should get clean clear beer every time!

Cheers,

— Michael Myers, Sergeant-at-Arms