Interesting 2009 article by MB Raines about yeast propagation, care and maintenance: (Link)
This bit fought my attention:
Seems to indicate that continuous stirring is the way to go, for a starter; so I’ve made myself a little magnetic stir plate using an old PC fan and some rare earth magnets.
The other bit that seems interesting is this:
“In terms of propagation, the closer the starter media is to the fermentation wort the better. A wort with an original gravity of 1.040 works well for most fermentations and is recommended for use in most brewing situations. If pitching into a high gravity wort, a standard starter may get shocked from the change in osmotic pressure. In this case a higher gravity starter (O.G. =1.065) may be necessary. Lower gravity starters (O.G. = 1.020) are commonly used by homebrewers and routinely produce higher concentrations of yeast but do not perform well when pitched into normal brewing worts. Presumably this is due to osmotic shock.”
Hmmm.... perhaps I’d better start paying more attention to how much spraymalt I chuck into that starter flask...
This bit fought my attention:
Seems to indicate that continuous stirring is the way to go, for a starter; so I’ve made myself a little magnetic stir plate using an old PC fan and some rare earth magnets.
The other bit that seems interesting is this:
“In terms of propagation, the closer the starter media is to the fermentation wort the better. A wort with an original gravity of 1.040 works well for most fermentations and is recommended for use in most brewing situations. If pitching into a high gravity wort, a standard starter may get shocked from the change in osmotic pressure. In this case a higher gravity starter (O.G. =1.065) may be necessary. Lower gravity starters (O.G. = 1.020) are commonly used by homebrewers and routinely produce higher concentrations of yeast but do not perform well when pitched into normal brewing worts. Presumably this is due to osmotic shock.”
Hmmm.... perhaps I’d better start paying more attention to how much spraymalt I chuck into that starter flask...
Also airlock is bad so it must need oxygen for this stage of life. Ties in well with aeration of wort needed for the growth phase.
