While reading an article on home brewing the article said to keep the tails, what does it mean by tails? What are the tails?
Tails or Tailings is what's left of a material after it has been processes and something more valuable has been removed. Though a term used in mining more than homebrewing.
In brewing this will refer to making use of...
1) Second runnings from a mash, parti-gyle. Great for a second a batch of a smaller beer or for yeast starter wort.
2) Making use of spent grain for baking or compost
3) Yeast trub. The gunk on the bottom of the fermentor. This is mostly yeast, hops, etc. Use this to grow more yeast, or even pitch a seconds batch of wort right on top.