Gyle is a portion of unfermented beer wort that is reserved for or added to finished beer for condition (carbonation).
What you can do is save a measured amount of your fresh unfermented sterile wort and store it in a sterilized, sealed container in your refrigerator. The gyle should be taken from the wort before yeast has been added to it.
Then when the beer has fully fermented and it is time to bottle, you can use the stored gyle by adding it to the finished beer.
The question is; ""How much wort should be set aside as gyle?"" The sugar content and specific gravity of wort will always vary. Here is a decent formula to calculate, rather accurately, the amount of gyle you will need to save in order to prime any volume of beer.
The formula is:
Quarts of gyle = (12 x gallons of wort) ________________________(÷) (specific gravity - 1)(1000) For example, for 5 gallons of wort that has a specific gravity of 1.052: Quarts of gyle = (12 x 5) ________________(÷) (1.052 - 1)(1000) Quarts of gyle = 60/52 ˜ 1.15 quarts ˜ 1.2 quarts