How to determine if my Starter has enough cells?

[Alex Southern]

Greetings,

My first post ahead of my first attempt at all grain.

I have 2 packets of white labs liquid yeast (WLP830) delivered next day, but they were at room temperature for 2 days before I was able to get them into my fridge. The packaging date was 24-JAN-18, so as of this post they are calculated at 63% viability.

My question is, given that i'm planning to make James Morton's Munich Helles Lager (from his Brew book). OG 1.046-1048, Batch Size 20 litre how should I work out how much light DME and water I need to get to the target 350 billion cells reportedly needed (using https://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/).

I understand that the room temperature issue will accelerate the degradation of the yeast, but by how much I don't know, so I don't know if I need to build up the starter in 2 phases for example.

Planning to use a 4.7 litre demi-john for the starter if that helps.

Any help would be appreciated.

Thanks
Alex

 

[Bostrows128]

If you can spare 10ml of that stuff you can use this method....

the important part starts at 16:00min mark.

 

[Alex Southern]

Hi

Thanks for the response.

Regarding the method discussed in the video. Is there any reason you can think why it must be 10ml? Why not 5ml? Or 15 ml?

Also why 1/10? is there any reason why I cannot just put 10ml yeast to a jug and fill with water until it becomes clear, and then measure the amount of liquid I’ve added? That ratio should then be relatable to the cell count if understand correctly. I think this would be more accurate as well, as tge estimated cell count would not be discretised to the dilution ratios chosen.

Or is the thickness of the gravity jar important somehow for determining the clarity/turbidity?

Thanks
Alex

 

[mulletmaster]

Depending on the packaging of the yeast the viability may be higher than online calculators predict.

https://www.whitelabs.com/news/purepitch-shelf-life

 

[Bostrows128]

Hi

Thanks for the response.

Regarding the method discussed in the video. Is there any reason you can think why it must be 10ml? Why not 5ml? Or 15 ml?

Also why 1/10? is there any reason why I cannot just put 10ml yeast to a jug and fill with water until it becomes clear, and then measure the amount of liquid I’ve added? That ratio should then be relatable to the cell count if understand correctly. I think this would be more accurate as well, as tge estimated cell count would not be discretised to the dilution ratios chosen.

Or is the thickness of the gravity jar important somehow for determining the clarity/turbidity?

Thanks
Alex

you can use any starting amount you want, I just found 10mls to be easier. To the jug you talk about it would be more difficult to do it that way than what is discussed in the video mainly because you would have to do a lot more calculations. And as the thickness, no, mainly because this will give you a rough estimate not exact so it won't matter, just try and use the easyest thing to tell if its transparent.

 

[jan_b19]

The calculator you used is usually spot on. If you're unsure about the required amount of cells, step up the starter.
Better to be a few billion over the recommended amount than to be under.
If you are using the method described above, be careful because by using some of the liquid yeast you will have less yeast cells in the package.
So adjust this when calculating.
Standard amount of DME for a starter is 1 part DME to 10 parts water. So for a one liter starter you need 100 grams of DME.
The issue I see with the method used above is that dead yeast cells will also make the water cloudy (or unclear) It's a good method when using fresh, live yeast.

 

[Bostrows128]

The calculator you used is usually spot on. If you're unsure about the required amount of cells, step up the starter.
Better to be a few billion over the recommended amount than to be under.
If you are using the method described above, be careful because by using some of the liquid yeast you will have less yeast cells in the package.
So adjust this when calculating.
Standard amount of DME for a starter is 1 part DME to 10 parts water. So for a one liter starter you need 100 grams of DME.
The issue I see with the method used above is that dead yeast cells will also make the water cloudy (or unclear) It's a good method when using fresh, live yeast.

I suppose I should have stated that it was only a viable method when the yeast is fresh, however, it is a good way to find base yeast so you can calculate viability later.