Blending yeasts by weight?

[Lacasse93]

In the past, whenever I have blended yeasts it was simply done by pitching to pouches or tubes at once. I typically brew smaller batches so I am not concerned with under-pitching. That being said, I would like to step up my yeast management and start making blends that are more complicated than 50/50. My problem at this point is, I do not know the best method of creating these ratios.

Like the title states, I am considering doing this by weight but do not know if this is the smartest. So say a pouch of white labs weighs 20 grams and I want a ratio of two yeasts at 70/30, do I just do the math involving weight or does volume make more sense? In theory a 70/30 blend would be 14 grams of one strain and 6 grams of the other. Does this all make sense or am I missing something. I am sure cell count factors in but just do not have enough experience to run this on my own without running it by everyone.

P.S the weights I used above were just random based on easy round numbers, I do not actually know how much yeast is in a pouch of white labs.

 

[eric19312]

I've also done the two full packs like you mentioned. In your situation if you want to do something complicated I'd probably try to base the blend on cell counts. You can mix the pack with water to make up 100 mL or 200 mL thin slurry and then use a calculator to determine viability.

So starting count x viability = total cells / standard volume then measure appropriate amount of each thin slurry. I mention making into a thin slurry because I think that will be easier to measure.

If you are using dry yeast I guess measure by weight of dry yeast.

 

[Vale71]

There are variations in average cell mass between strains but they're quite small. IMHO you'll be perfectly fine using weight to determine blend ratios. I don't think you'll be able to taste the difference in any case if instead of, say, the 70/30 ratio you're aim for you actually end up with 72/28 or 69/31.

 

[Lacasse93]

There are variations in average cell mass between strains but they're quite small. IMHO you'll be perfectly fine using weight to determine blend ratios. I don't think you'll be able to taste the difference in any case if instead of, say, the 70/30 ratio you're aim for you actually end up with 72/28 or 69/31.

Ok this would be more than fine. My add on from here would be what percentages to we think we start perceiving differences? Like would there be flavor impacts at a 90/10 ratio or are we thinking it would need to be higher?

 

[eric19312]

There are variations in average cell mass between strains but they're quite small. IMHO you'll be perfectly fine using weight to determine blend ratios. I don't think you'll be able to taste the difference in any case if instead of, say, the 70/30 ratio you're aim for you actually end up with 72/28 or 69/31.

I was thinking the liquid yeasts might be from different vendors. That white labs yeast comes out of the pouch like toothpaste, some of the other vendors seem to have more liquid in their packages. So if the white labs yeast is say 10 billion cells per mL wyeast might be 3 billion per mL. If you wanted a 70/30 blend you might want 7 mL of the white labs and 10 mL of the wyeast (numbers are made up purely to show the math). Would also work for yeast you are ranching in your fridge. It is always going to be approximate but at least a reasonable starting point.

 

[eric19312]

Ok this would be more than fine. My add on from here would be what percentages to we think we start perceiving differences? Like would there be flavor impacts at a 90/10 ratio or are we thinking it would need to be higher?

Scott Janish talks about doing this with wine yeast in The New IPA. Mentioned ease of combining yeasts when working with dry yeasts. He was using 5-10% wine yeast with S-04.

 

[Steveruch]

What are you trying to accomplish with mixing yeasts?

 

[Lacasse93]

What are you trying to accomplish with mixing yeasts?

Help boost attenuation while adding a bit of the flavor profile

 

[Beermeister32]

Subsequent batches of mixed yeast strains can change the flavor profile if one strain becomes more dominate than the others.

 

[Lacasse93]

Subsequent batches of mixed yeast strains can change the flavor profile if one strain becomes more dominate than the others.

Sure but couldnt I just prop up the two batches separately and keep them in two different containers and only blend part of them? So that way any time I want to use this blend I would just go back to the two jars and make it again

 

[Beermeister32]

Perfect! (Historically, brewing yeasts were a bunch of mixed strains until Carlsberg isolated individual yeast strains.)

 

[eric19312]

Sure but couldnt I just prop up the two batches separately and keep them in two different containers and only blend part of them? So that way any time I want to use this blend I would just go back to the two jars and make it again

Yes but now we are back to liquid yeasts. Getting any level of precision on the ratio would be a fair amount of work. Would be much easier to stick with dry yeast.

 

[Qhrumphf]

Weight is probably very close. If you happen to have a microscope and a hemocytometer, getting an actual cell count would make volume even more accurate

Scott Janish talks about doing this with wine yeast in The New IPA. Mentioned ease of combining yeasts when working with dry yeasts. He was using 5-10% wine yeast with S-04.

Haven't read it, but curious about this. Most wine yeasts are killer yeasts and I'm pretty sure S-04 (like almost all beer yeasts) is susceptible to killer yeast. I can only assume he's using a non-killer wine yeast. But something anyone else trying this would also need to keep in mind. Wouldn't work with any old wine yeast (though I'd be surprised if Janish neglected to mention that).

 

[eric19312]

Haven't read it, but curious about this. Most wine yeasts are killer yeasts and I'm pretty sure S-04 (like almost all beer yeasts) is susceptible to killer yeast. I can only assume he's using a non-killer wine yeast. But someone anyone else trying this would also need to keep in mind. Wouldn't work with any old wine yeast (though I'd be surprised if Janish neglected to mention that).

He was talking about using 58W3 5-10% with S04. Also did some work with QA23 and 71B-112. 58W3 is killer neutral per the manufacturer. Also working with something called Alchemy 2. A lot of his experiments show up in blog posts easy enough to find if you don't have the book.

 

[Qhrumphf]

Not familiar with any of them (heard of the Lalvin one but that's it). Looked up 58W3 and saw

• Allows for the release of bound terpenes in aromatic varieties due to the beta-glucosidase activity. This enhances classic varietal characteristics.

And immediately understood the goal here.

 

[mashpaddled]

Weight is a fine approach. Anything you can consistently repeat will be suitable here. Volume would be fine, too. A mass of billions of yeast cells isn't going to have that much variability.

What is going to potentially defeat your ability to consistently repeat is if you are using slurry from prior batches you would need to account for the volume/weight of trub. That might be a good reason to yeast rinse.

 

[tbaldwin000]

I brew with a lot of blends. I do it by building separate starters for each yeast from a few billion cells. Basically if I want about 50bn cells of yeast A and 150bn cells of yeast B, then I'll make a starter using (50/1.5) = 33.3g DME for yeast A, pitching a few ml of yeast (a few billion cells, basically) into that starter, and then putting it on the stir plate and letting it finish. I'll follow the same procedure for yeast B, but with 100g of DME as I want 3x the cells.

The growth number of 1.5bn cells per gram of DME in a well stirred starter is an estimate from Kai's yeast growth experiments. I have found that to work consistently, as opposed to the other yeast starter calculators which frankly make no sense and don't conform to my results.

 

[eric19312]

What is going to potentially defeat your ability to consistently repeat is if you are using slurry from prior batches you would need to account for the volume/weight of trub. That might be a good reason to yeast rinse.

I am surprised, was thinking the slurry would be bad idea due to drift of the ratio. White Labs disagrees in a post I found about pitching yeast blends:

Q: Won’t it be hard to collect the yeast?
A: Yes and no. It will be hard to collect the same percentage every time, but we don’t use yeast that much anyway. It won’t change that much over 5 to 10 generations. And if you only go 3 or 4, it is not that much extra of a cost if you get your target results.
https://www.whitelabs.com/beer/using-multiple-yeast-strains

I think there is a missing word in the part about we don't use yeast that much anyway but the key is the not changing much over 5-10 generations...The challenge here would be brewing the first time with a 50/50 blend and then the second time with a 75/25 blend to see if you prefer one over the other. Probably in this case best to do them side by side with same starting stocks and then keep the blend you liked best for future batches.

I don't agree with point above on yeast rinsing. If you really care to know the number of cells in your slurry I think you need a microscope.