Brewtan B can be used in two ways;
Added to the water at the beginning of the process. When used in this way it will improve the flavour stability of the beer by removing excessive iron and other metal impurities, which may be in the supply water, and by acting as an antioxidant. Typically, an addition of 60mg per litre is used in breweries but up to 100mg per litre would be Ok to use in homebrew. Just dissolve the Brewtan directly into the brew water before adding anything else. Make sure the Brewtan is fully dissolved, sometimes it may be easier to produce a 10% solution in tepid water and use a high-speed stirrer/mixer to produce a clear tea coloured solution.
Added to the beer after fermentation to improve shelf life and to remove proteins, which can cause cloudy beer. Use a dosage of about 40 to 60mg per litre at this stage. The tannin will combine with unstable proteins and will precipitate out as a sediment. Tannin-protein complexes tend to be light and can produce fluffy bottoms, lowering the temperature or adding finings after a short period of time following the Brewtan addition can help consolidate the sediment. The Brewtan needs to be added as a solution in water at this point, do not dissolve in beer. It needs to be mixed in as quickly as possible so that all the beer is treated, as it has an instantaneous reaction. Transfer the fermented beer from your fermenter to your keg or bottling vessel, being careful not to pick up sediment, and add the Brewtan solution, stirring in well to ensure good mixing.
At this stage it will give complete stabilisation for small pack beer.