2 Yeast Porter

[dmaxweb]

I fermented a porter using US-05 and some Fullers strain I had. I harvested the yeast from the secondary just in case. We'll, the porter turned out great. After letting the slurry settle in a gallon jug, I decanted all but 2 pints. There are three layers in the jars. Since Fullers is very flocculant while US-05 is only medium, am I seeing the Fullers yeast on the bottom, a layer of trub and the US-05 on top?

 

[kinnebrewer]

When combining 2 yeast strains, typically 1 will win out during fermentation. In other words, it is more likely they you have 1 yeast strain sitting at the bottom of your gallon jug. My guess would be 05, due to its versatility and durability (just a guess though). The bottom layer would be trub, dead cells, proteins, etc. the middle layer would be your healthier yeast, and the top layer would be some combo of yeast and liquid.

 

[dmaxweb]

I understand what you're saying but in this case there are 3 layers under the liquid. These are the pint jars from the gallon jug after I decanted all except 2 pints. I could be wrong, but the middle layer looks like trub to me.

 

[Arimanari]

There are quite a few European beers being made with 2 strains.. English breweries have a very long history (and tradition) doing that, but those are strains they've been working with for a very long time. I won't rule out that two strains can *share the load* during fermentation and contribute to the beer simultaneously, but it requires planning and testing.

 

[dmaxweb]

The porter has been in the kegs at 39F only a week. I typically age ales 3 weeks before serious sampling. We'll see.

 

[bike2brew]

I fermented a porter using US-05 and some Fullers strain I had. I harvested the yeast from the secondary just in case. We'll, the porter turned out great. After letting the slurry settle in a gallon jug, I decanted all but 2 pints. There are three layers in the jars. Since Fullers is very flocculant while US-05 is only medium, am I seeing the Fullers yeast on the bottom, a layer of trub and the US-05 on top?
View attachment 792239

Really good question. I am not going to pretend to answer based on what I have heard or read somewhere. I think the only way to know for sure is to sample the 3 layers and analyze by culture and morphology.

 

[dmaxweb]

I'm thinking about decanting all but the bottom layer and making a 1 liter starter see if it takes off and the aroma.

 

[dmaxweb]

After further consideration, there's a local craft brewery nearby that uses the Fullers strain. I got some slurry from them from them several weeks ago. I'll just get some more. I have some fresh US-05. I can just use both of them if I want to.
Overthinking the process is giving me a headache

 

[dmaxweb]

Fresh Fullers slurry I got a several weeks ago.


US-05 from last week

 

[bike2brew]

After further consideration, there's a local craft brewery nearby that uses the Fullers strain. I got some slurry from them from them several weeks ago. I'll just get some more. I have some fresh US-05. I can just use both of them if I want to.
Overthinking the process is giving me a headache

I am sure it will make good beer but does not answer the original question (hypothesis). Your logic (intuition) on the stratification is sound. Layer 1: yeast ?, layer 2: traub (mix of hop bits, junk), layer 3: yeast?. This should be easy enough to test once you have samples collected and cultivated on an agar plate. I am sure the morphological characteristics for 05 are available somewhere for you to test the 2 suspects by observation with the hypotheisis that isolate 1 (2) is 05 or not 05; once you have identified one as 05 you can infer the other by process of elimination. Helpful if you knew what the other suspect looked like or had a description of its culture characterisitics.

Good luck and have fun. Could be a nice science fair project for your kid, or end of term microbiology project.

 

[mashpaddled]

When combining 2 yeast strains, typically 1 will win out during fermentation. In other words, it is more likely they you have 1 yeast strain sitting at the bottom of your gallon jug. My guess would be 05, due to its versatility and durability (just a guess though). The bottom layer would be trub, dead cells, proteins, etc. the middle layer would be your healthier yeast, and the top layer would be some combo of yeast and liquid.

That just isn't true. This is something that some homebrewer said and raced around the internet without any thought. I heard it when I started brewing over a decade ago and I'm sure it was out there a decade or more before that.

Unless you have killer strains involved (which do not include any commercially available beer strain) the different strains will live together. Sure, some more aggressive strains may have a larger population but they do not completely crowd out the other. What often happens is multiple strains actually benefit from existing together. Typically multiple strains produce a more attenuated beer because the strains take advantage of the fermentation characteristics and byproducts of the other strains.