Whirlfloc is a product you add at the end of the boil. It causes proteins in the boil to coagulate and clump together, reducing the amount of proteins that would otherwise stay in solution right through until the first time the finished beer is chilled (where it would then precipitate as "chill haze," causing the beer to be cloudy). It's basically the same thing as Irish moss (which is cheaper).
WLP002 is a liquid yeast from White Labs.
Irish Moss is a kind of seaweed which is dried and crushed up, and added to the wort near the end of the boil. It does the same thing as Whirlfloc.
*flocc is not a thing I'm aware of. "Flocculation" describes a yeast's propensity to clump together, which causes it to precipitate out of solution faster (because the bigger clumps weigh more). A "low flocculating yeast" is one that will take longer to fall out of solution, resulting in cloudier beer.
Gelatin is the same kind of gelatin that is on the shelf at your grocery store. You mix it up and add it to the beer after fermentation has finished. It helps "pull" precipitates out of suspension, assisting in clearing the beer. To prepare it, sprinkle 1 tbsp of it into 1 cup of room-temperature water. Leave it for 20 minutes to "bloom." Then heat it up in the microwave, 15-20 seconds at a time, until it reaches 150-160° F. DO NOT let it boil. Then stir to ensure it's dissolved, and pour it into the beer. If you can cool the beer beforehand (i.e., move the fermenter into a refrigerator a day or two prior to adding the gelatin), it will be much more effective.
I end up with very clear beer, because I take measures at several points in the brewing process. I do the following:
- At the end of mashing, I use a grant and a pump to recirculate the wort back into the mash/lauter tun until it's clear. Then I switch the output of the grant to the boil kettle instead of recirculating. This means that once I've started drawing runnings from the mash/lauter tun, I don't have to close the valve while switching to the kettle, then re-open it, which can disturb the grain bed.
- I use a hop screen to contain my pellet hops during the boil.
- I use Irish Moss in the last 10 minutes of the boil.
- I chill extremely quickly, using a plate chiller, a pump, and a cooler full of ice water. I get my wort from boiling down to 65° F in about 6-7 minutes.
- I recirculate my wort from the chiller back into the kettle during chilling, instead of going straight to the fermenter. Then, once chilled, I rack the wort from the kettle to the fermenter using an autosiphon. This allows me to siphon the wort from the "top down," getting all the clear stuff first, then at the end, I can stop the siphon once I get to the break-rich dregs at the bottom.
- I leave my beers for 3 weeks to ferment and begin clearing.
- I cold crash in a fridge.
- I add gelatin and leave it for another 3-4 days.
- I keg my beers, so after a couple more weeks in the keg, the beer is crystal clear.
