Simple yeast starter question

[thomasjr16]

After a year of all-grain batches, 26 total and 26 successful yeast starters from either a slurry or fresh liquid (store bought) yeast I had a "wait a minute moment"

I follow the 1g:10ml ratio and have always added DME for pre-boil starter volumes. My question is though, should I account for the boil off rate and adjust my DME amount down?

For example, if I add 1500ml to my e-flask and boil for 20 mins, I have about 1400ml left. Should the 1:10 ratio be for the pre-boil or post boil volume?

The pre-boil volume ratio is what I've used to make everything to date and it's worked fine, but I was curious what others did. Probably doesn't make a big difference either way.

Thanks

 

[Double_D]

My ratio ends up being a little higher than 1:10. I wouldn't worry about it. We brew in such small volumes

 

[WoodlandBrew]

Biomass yield is almost entirely driven by the amount of extract. Each gram of DME will yield about 1 billion cells. As long as gravity and pitch rate are within reason they have very little effect on yield.

So, you don't need to adjust the amount of DME you are using.

 

[Sippin37]

It's such a small difference you don't even need to worry. But in general, yes they are referring to the post boil volume.

 

[thomasjr16]

It's such a small difference you don't even need to worry. But in general, yes they are referring to the post boil volume.

Just for curiosity sake, and not scientific at all, I used the ratio for the post boil volume for a starter I made yesterday. The yeast were washed from a washed Belgian wit slurry that has been in my fridge for about 7 months. I used a stir plate as usual, and made a 1500 ml post boil volume starter and the yeast were showing signs of activity within 7 hrs and almost high krausen about an hour or two ago.

Probably dumb luck since it really shouldn't change much other than cell count, but the 1:10 ratio with post boil volume worked better than anything I've made a started for this past year, in terms of activity / krausen level.

 

[WoodlandBrew]

High activity normally indicates a high growth rate. Yeast growth can be thought of as a reaction. The rate at which the reaction occurs is proportional to the concentration of the reagents. So if you have a lot of yeast, or a high gravity wort the yeast will grow faster and show more activity.