Acquiring a New Strain

In most cases you acquire a new yeast strain either by buying a new Wyeast pack or by reculturing from a commercial bottle.

In the first case, I suggest you keep the package inactive until you actually intend to make a batch from it. You can then proceed as detailed in the preparing a starter section.

If you want to reculture yeast from a commercial bottle, first of all you should gather information on the yeast characteristics: is it a bottling strain or the primary fermentation yeast? Is it a pure strain or a multi-strain? Bottom or top fermenting?

If it is a pure strain, you can successfully try to reculture it, provided it has not been sitting in the bottle for too long. There is obviously no point in trying to reanimate dead yeast :-)

The usual precautions apply: scrub the table surface, culture tube and your hands with alcohol. Wear a mask, keep your work area as dust-free as you can, work in flame zone.

Have ready a culture tube with 10 ml of sterile wort and a sterile 1 ml pipette.
Proceed as follows:

  • Open the bottle and decant in a pitcher (you can enjoy it later...) leaving behind some beer and the yeast dregs
  • Flame bottle mouth
  • Swirl bottle to rise the sediment
  • Take the sterile pipette and hold with right hand, discard the aluminum foil
  • Flame the bottle mouth again
  • Plunge the pipette in the bottle and suck up 1 ml of suspension. The cotton plug in the pipette must not come into contact with the liquid
  • Take out the pipette, keeping it sealed with your right index finger
  • While keeping the pipette tip in the flame zone, take the test tube in your left hand
  • Grab tube cap with right hand little finger, unscrew by turning tube with left hand. Hold cap between the little finger and the palm of your right hand
  • Flame tube mouth
  • Working in the flame zone, release the content of the pipette into the test tube. Pipette and tube should never touch
  • Flame the tube mouth again and place cap back on, again using left hand to screw it
  • Put test tube in its rack and incubate in a warm (>27 °C) clean and dry place

Since the viability of the yeast cells you inoculated is probably very low, you might have to wait for several days before you see any sign of fermentation.
As soon as the wort starts fermenting, plate it for selection and storage.