« on: November 07, 2014, 07:05:56 PM »
I don't know if I've experienced it, but I know a couple ways you can prevent it.
Irish moss added in the last 15 minutes of the boil will help prevent it. Is Irish moss completely effective? I have my doubts. But it should help a lot, at least in theory.
If you brew all-grain, then a brief protein rest at 122 F for about 5 minutes will more certainly prevent protein haze, however this also comes at the expense of reduced body and head retention in the final beer, so limit it to 5 minutes or less to minimize this impact. In as little as 10 minutes at 122 F, your head and body will be poor in my experience, making for a very watery and lifeless beer, so don't figure "more is better" because it's not.
Also keep in mind that there are other sources of haze, including yeast, tannin, contamination, pectin, etc.
Gelatin will knock out yeast and contamination but not protein or tannin.
If memory serves, the tannins can react with phenols to form a haze that in theory can be reduced using Polyclar which is essentially a powdered plastic. Again, personally I have my doubts whether this does anything, as it hasn't helped in cases where nothing else worked and I was pretty sure I had this kind of haze. But of course you're welcome to try it if the other stuff doesn't help.
I'm not really an expert on water chemistry but I'll bet it can have a huge effect on haze if there is too much or too little mineral content. Someone else will probably chime in about this.
In fruit beers and ciders, pectin haze can be minimized through use of pectic enzyme added to the fruit before the fruit is added to the beer or cider. If you don't treat the fruit and the pectin sets in, I don't know if it's possible to remove it -- I'm not saying that you can or cannot, I'm just saying that I personally truly do not know if it is possible or how to do it. Again, someone else out there knows more than I do.