This is a basic video on how to harvest yeast from a previous batch of beer. All you need are some pint mason jars which you can get at Walmart or online at Amazon very cheaply. After you have a beer that is done fermenting leave all of the yeast cake at the bottle. Boil 4 mason jars for 15 mins. Remove the mason jars and fill them with the boiled water. Let them come to room temperature. At this point add the water from the 4 mason jars into the bucket with the yeast cake and swirl the bucket for about 30 seconds and then let it sit for 20 mins. After the 20 mins pour off the yeast sediment into the jars and then let them sit for about 1 hour. After the hour pour off the top layer of sediment in the jars into 2 additional mason jars. Try to pour off just the cloudy top layer and leave the trub behind. This is your final product. Make a yeast starter with the 2 jars you have harvested for better results.