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Culturing From a Single Cell
‘One man and his yeast’
by Phill Turner
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What is it?
• Or selecting several
groups which gives
diversity in case of
mutation to use for
fermentation
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• Growing yeast cells on
a agar plate, which
multiply from a single
cell, and taking one
group to use for
fermentation
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From one cell to billions
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Reasons for doing
it?
o Originally there were not many yeasts available
o Potential infections in bottled beers
o Keeping your own house yeast that has
adapted to your brewing system
o Personal enjoyment, if you are just a bit of an
nerd or anorak like me
o To obtain yeast that isn't available elsewhere
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Basic Equipment Needed
❑ Pressure cooker or autoclave
❑ Bunsen burner or camping stove
❑ Loops, various types
❑ Various sized glass containers that can be
autoclaved
❑ Malt extract or wort
❑ Petri dishes or plates (plastic or glass)
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Reasons for sterilising
in a pressure cooker
• If you boil, you will kill the bacteria but you will not kill
the spores
• They need to go to a higher temperature of 1210C
for 10-15 minutes or 1340C for 3 minutes
• Dry heat at 1600 for 2 hours
• Tyndallisation
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Sterilising
1210C for 15 minutes
Pressure Cooker Autoclave
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Flame Source
Safe working area A camping stove is sufficient
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Figure 6.1: The updraft of a Bunsen burner creates a dean
work area.
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Loops
• disposable one from
£2.50 a pack of 10
• Reusable, various prices
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Glassware
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Making plates
Agar melts at 950C Solidifies at 450C
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Choosing Your Yeast
• Yeast is a single cell fungus
• Beer, wine and bread yeast are all closely related
• Yeasts adapt to their environment
• What characteristics are you looking for?
• Are you choosing a yeast to brew a certain style?
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• Inoculate a small vial of
wort with yeast
• Once it is fermenting,
plate onto the Petri dish
• Either directly or by
diluting the wort first
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Plating out
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The Growing Yeast
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Undiluted and diluted wort
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Choosing your colony(ies)
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Sterilising the loop
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Cooling the loop
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Selecting a colony
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Flaming the vial
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Transfer to the starter
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Flame the vial again
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Replace the cap
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4 days
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12 hours later
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