Cold crashing is a simple method that accomplishes 2 purposes. First, it allows the trub (layer of dead yeast and byproducts on the bottom of the LBK) to compact. Why is that good? Because more beer comes out of the spigot before the trub SLOWLY makes its way to the spigot. Second, cold crashing allows the beer to clarify, as particles fall out of suspension and settle to the bottom. I personally don't care about clear beer, but I do want to get every drop out of the LBK. If you're making a wheat beer, the second goal probably isn't something you want to have happen. How do you cold crash? Well, it's very difficult so I'll lay out the steps below. Please study them carefully before undertaking this difficult task. 1) When your beer is ready to bottle (determined by waiting 3 weeks and or testing with a hydrometer and getting matching readings 48 hours apart), pick up the LBK. 2) Walk over to your refrigerator. 3) Open the refrigerator door (or have someone else do it so you don't drop the LBK). 4) Put the LBK inside the refrigerator. 5) Close the refrigerator door. 6) Leave it in the refrigerator for 24 - 72 hours (it will thicken in 24 hours, takes 72 to settle the particles). On bottling day, prep everything and remove the LBK only when you're ready to bottle - you don't want to warm it up and undo all the difficult work that you accomplished. Questions: 1) Does cold crashing kill the yeast? - No, it just puts them to sleep. 2) Does cold crashing impact how my beer will carbonate? - No. Yeast wake up and it carbonates fine. Remember to angle your LBK during fermentation, and cold crashing (and bottling) to keep the trub away from the spigot. See this post: http://community.mrbeer.com/topic/32908-propping-up-your-lbk-no-trubal/ First picture below shows the inside of my LBK after bottling my latest brew. I have about an ounce, if that, of liquid left in there with the trub, which you can see in the 2nd picture (a little milky at that point because I sloshed it taking the pic). I had 5 gallons of liquid split between two LBKs, and that gave me 600 ounces of beer or 93.8% of what I started with. The most I've ever gotten is 614 ounces.