Fining Agents – Improving Beer Clarity

by Brad Smith on December 30, 2008 · 29 comments


The clarity of homebrewed beer is cherished for many beer styles. Fining agents added at the end of your boil step or later in the fermenter can help to rapidly clear your beer.

I previously covered a range of techniques to help clear your beer in our article on clarity. This week we zero in on one particular technique – the addition of fining agents. A fining agent is a compound added to beer to aid in precipitating and binding with compounds that reduce clarity.

Fining agents generally have large molecules that are positively charged. These charged molecules attach themselves to negatively charged contaminants and then precipitate them out of the finished beer – helping these contaminants rapidly settle to the bottom of the fermenter.

The three haze producing contaminants affected by finings are: suspended yeast, proteins from the malt, and polyphenols which can come from both hops and malt. A fourth cause of haze is microbiological contamination from infection, but finings will do little to help mitigate infection – so cleanliness at every stage is still important.

Finings may be added either at the end of the boil or in the fermenter. Irish moss and whirlfloc tablets are used at the end of the boil, primarily to precipitate proteins during the cold break. Finings for the fermenter are added a few days before bottling or racking to precipitate yeast, proteins and polyphenols. These include chillguard, gelatin, isinglass and polyclar.

For boiled finings, often called “copper finings”, these should be added in the last 10-15 minutes of the boil, as boiling them longer often reduces their effectiveness. Finings added in the fermenter are usually added 4-5 days before bottling or racking the beer to give the fining time to precipitate yeasts and proteins and keep these out of the finished bottle or keg. Care must be taken when adding these finings as the large molecules can create an effect called “nucleation” which releases carbon dioxide stored in the beer, and can lead to a gush of rapid foaming.

Irish Moss

Irish moss is a dried additive derived from seaweed. It is added in the last 10-15 minutes of the boil to aid in coagulation and precipitation of proteins during the cold break. Approximately 1 tsp is needed per 5 gallons of wort. Irish moss does a great job reducing protein haze in the finished beer, and you can actually see clumps of protein form and drop out at the end of the boil when it is used.

Whirlfloc Tablets

Whirlfloc tablets, like Irish moss, is derived from seaweed, but also includes additional purified carrageenan, which is the active ingredient in Irish Moss. One tablet is added per 5 gallons of wort during the last 10 minutes of the boil. Since it shares the same active ingredients as Irish moss, whirlfloc does a great job precipitating proteins at the end of the boil.


Chillguard is a silica gel that is used in the fermenter a few days before racking or bottling. To use chillguard, dissolve ½ tsp into ½ cup of hot, but not boiling water and gently mix it into 5 gallons of beer. Chilguard is primarily effective in precipitating proteins.


Common unflavored clear gelatin can be purchased from the local grocery store and is effective in reducing both proteins and polyphenols. Gelatin is a collagen based agent derived from hooved animals. Add 1 tsp of unflavored gelatin to a cup of hot, but not boiling water and gently mix it into your fermenter. Again, wait a few days before bottling or racking to allow the gelatin to clear the beer.


Isinglass is also a collagen based additive derived from fish bladders. Used primarily by commercial brewers, isinglass is effective against all three major barriers to clarity: yeast, proteins and polyphenols. Isinglass in its pure form must be mixed with an organic acid before use, but many types of isinglass sold for homebrewer use are so called “instant” variants that come premixed with the acid needed for preparation. Be sure to follow the directions that came with your isinglass. Typical application rates are ½ tsp mixed with 1 cup of hot water per 5 gallons of beer, and allow 4-5 days before racking or bottling.


Polyclar is an additive that consists of powdered PVPP plastic. The plastic is positively charged and very effective at removing polyphenols from finished beer. Polyclar is added in the fermenter at the rate of 2 tablespoons per 5 gallons. Again, the polyclar is usually mixed in a cup of warm water first and then gently mixed into the fermenter. Allow 4-5 days for the polyclar to work before bottling or racking.

The fining agents above are the ones most commonly used by homebrewers. Note that often it is best to use a combination of techniques if you want to attack cloudiness caused by proteins, yeasts, and polyphenols all at once.

I personally use Irish Moss on any beer style where clarity is important, and then use some judgement as to whether to add additional finings at bottling based on the state of the beer at that point. Naturally you don’t want to discount other methods such as rapidly chilling wort, choosing high flocculation yeast and cold storing your finished beer.

Thanks again for joining us on the BeerSmith home Brewing Blog. Please subscribe or place a vote on BrewPoll if you enjoyed this week’s article. Have a great week.

Enjoy this Article? You'll Love Our BeerSmith Software!
  Don't make another bad batch of beer! Give BeerSmith a try - you'll brew your best beer ever.
Download a free 21 day trial of BeerSmith now

Previous post:

Next post: