Do I have enough yeast?

[brewthrough]

Howdy! Lurker for a while and here's my first question.

I've harvested some Chimay yeast from bottles. I've used a 1L(~1quart) [size of the jar in the picture] 1.044 starter (aimed at 1.040 but got a bit more). There's quite a bit of trub because I made the starter with grain. I was planning on using it for a brew tomorrow, but I'm not sure if I have enough.

I've also opened it (oh man, it smells really nice :cross: ) to take a reading with a refractometer and I got 1.011 (using Northern Brewers refractometer calculator).

For info, I brew small 9L BIAB batches. So, do I have enough yeast? If not, should I pour the beer on top and rack a new starter?

Thanks!

 

[BigFloyd]

For a 9L batch, it looks like you have enough. I'd want to cold crash that 24 hrs before decanting off the starter beer if you can.

 

[brewthrough]

For a 9L batch, it looks like you have enough. I'd want to cold crash that 24 hrs before decanting off the starter beer if you can.

Fantastic! I don't have 24 hrs, but something between 12 and 16.

Thanks for answering! Wish me luck!

 

[eddiewould]

Assuming the starter ferments to completion, the final cell count is mostly dependant on the amount of fermentable matter. The initial cell count is not a huge factor.

 

[brewthrough]

Assuming the starter ferments to completion, the final cell count is mostly dependant on the amount of fermentable matter. The initial cell count is not a huge factor.

I agree with you. My question is then: how does one calculate the final cell count from the amount of fermentable matter?

There are calculators for starters, but they need the "Initial Cell Count" as input.

 

[Michigan_Wolfman]

If it doesn't blow the lid off your fermenting bucket, you're just right.

 

[eddiewould]

I agree with you. My question is then: how does one calculate the final cell count from the amount of fermentable matter?

There are calculators for starters, but they need the "Initial Cell Count" as input.

Playing with the calculators, it looks as though 1L of 1.040 starter will yield roughly 140 billion cells plus whatever cells were already there on a stirplate. So you should be absolutely fine.

 

[eddiewould]

Playing with the calculators, it looks as though 1L of 1.040 starter will yield roughly 140 billion cells plus whatever cells were already there on a stirplate. So you should be absolutely fine.

According to the calculator on homebrewdad:

For stirred starters, if the initial cell count is less than 1.4 billion per gram of extract, the growth rate is 1.4 billion cells per gram of extract.

 

[brewthrough]

Playing with the calculators, it looks as though 1L of 1.040 starter will yield roughly 140 billion cells plus whatever cells were already there on a stirplate. So you should be absolutely fine.

Unfortunately I didn't use a stir plate. I was going to build one, since I have a fan and magnets, but don't know where I put them. Finally, I just shook the jar and let it sit.

 

[brewthrough]

Woohhoooo! It's bubbling like crazy!


Thank you all!

 

[brewthrough]

Woohhoooo! It's bubbling like crazy!


Thank you all!

Well, it stopped bubbling after some hours. Possible causes:

- I crashed the yeast: I put the fermenter in a water bath (after fermentation started), since ambient temps were going to be 86F outside

- I underpitched...

- Fermentation is still going but not so vigorously


Since then, I've taken it out of the water bath and given some shakes. I also took a reading today and it is at 1.029, so obviously not finished. Tomorrow or 2 days after today I'll take another and check if it really stopped fermenting.


If it is the case, I'll probably pitch some Safbrew abbaye yeast. Despite not being great, it's the closest I have here. I could re-harvest Chimay's yeast, but it would take time.

 

[eddiewould]

Well, it stopped bubbling after some hours. Possible causes:

- I crashed the yeast: I put the fermenter in a water bath (after fermentation started), since ambient temps were going to be 86F outside

- I underpitched...

- Fermentation is still going but not so vigorously


Since then, I've taken it out of the water bath and given some shakes. I also took a reading today and it is at 1.029, so obviously not finished. Tomorrow or 2 days after today I'll take another and check if it really stopped fermenting.


If it is the case, I'll probably pitch some Safbrew abbaye yeast. Despite not being great, it's the closest I have here. I could re-harvest Chimay's yeast, but it would take time.

Some other possible reasons why it's not bubbling:
- Airlock / lid not sealing perfectly - it's still going
- Yeast ran out of nutrients / O2
- You selected for early floccing / lazy yeast with your harvest
- Wort is not very fermentable for some reason.

 

[Michigan_Wolfman]

+1 On what eddie said. Keep us posted.

 

[brewthrough]

Yeah, it's stuck at 1.029 for at least 2 days. I think I'll pitch some Safbrew Abbaye. Does anyone see a problem with this?

EDIT: Also, when pitching, should I shake it to aerate or now that is partially fermented, it will do more bad than good?