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Whirl floc tablets are an enhanced blend of Irish moss and purified carrageenan that aids in the coagulation and settling of haze-producing proteins and beta glucans. Use one tablet per 5 gallon batch and add it with 5 minutes remaining in the boil. Yes, 5 minutes is correct. According to the manufacturer, if Whirl floc is in the boil for any longer than 10 minutes, the active ingredients become denatured and therefore will not do their job.