There seems to be many methods for using gelatin to clarify homebrew. After doing some interwebs searching, I found one basic way to do it that seems to work for me. Your mileage may vary.
Obtain Gelatin – the Grocery store type works just fine. Knox brand comes in easy to use and easy to store packets that most everyone should be able to find. 1 Packet of 0.25 oz should work for 5 gallons of beer.
1- Place 1 cup cool water in a small sanitized saucepan.
2 – Open packet and pour onto the cool water. Let sit 20 minutes to “bloom” or soak up some of the moisture. Don’t skip this step.
3 – Slowly heat the pan to about 170 F stirring with sanitized spoon to dissolve. DO NOT BOIL!
4 – When the mixture reaches 170 F, remove from heat and cover with sanitized lid. Let the pan cool a little. Don’t let this sit too long and cool too much, it can solidify in the pan.
5 – You can now add to your bottling bucket for bottling or directly to the keg or carboy before adding beer.
I like to add my priming sugar mixture and the warm gelatin mixture to my keg / bucket and rack my beer on top to allow it to mix in without stirring the beer. Also, I have mixed the beer / gelatin in the keg by purging the keg with co2, and then agitating the keg, turning it upside down etc. I’ve forgotten to add gelatin to a carboy in the past, and they attempted to add it ontop of the beer once it was already in. I didn’t seem to get any clarifying benefit on that batch. I assume this happened due to it not mixing in very well by just dumping ontop.
Some other conflicting information I found was some people saying not to add gelatin to room temperature beer, as this may make your beer even cloudier. I can’t say if this is true or not. If you have the ability to chill your beer first to bring out any chill haze, you may get an even better result, but I have not tried that. I’ve used the gelatin in both carboys for secondary and in the keg and I have had visible results in rapid clarity. Its probably the same clarity you would get by naturally letting the beer clear over time and or with with cold conditioning, but with gelatin it just happens faster. Also you may get added benefit by adding polyclar at the same time if you are racking to a secondary.
Let me know if you try this, and how it works for you.