So I was just looking back at past batches I've used F1 and was looking at my attenuation. I've used F1 three times now. My attenuation went like so...
1st = 92%
2nd = 90%
3rd = 88%
Anyone else sensing a trend here?? It's got me a little worried. I think I know what I should do, but was hoping for advice as well. I'm relatively certain I know why this is the case. I overbuild all my starters to harvest off 500 ml of clean starter/yeast. I then crash that out and decant, and save the yeasties in 50 ml tubes in the fridge. Ergo, when I am ready to brew with this yeast, I take a 50 ml tube out and build another starter and proceed as usual saving 500 ml. What I am getting at here is, each time I use the yeast it's a generation older.
In hindsight, I should have been splitting the slurry between, I dunno, three 50 ml tubes so I would have three tubes of X generation. Does that make sense?
Point being, hopefully I can slow this downward trend in attenuation by keeping more samples of given generations. But is there anything else I can or should be doing? I don't want to end up with like 50% attenuation the 25th time I brew with this!
Those are some good points. I hadn't thought of it that way. What you said makes sense (about harvesting from a starter not being a new gen).That's the same method I use other than saving some of the slurry itself sometimes. I always thought the idea was that the yeast saved from the starter isn't considered a new generation, only the yeast saved from slurry since the slurry is the yeast that fermented a whole batch. Was it the same recipe, maybe your mash temps changed as well?
Ahh that makes sense as well. I agree with you.I do consider yeasts harvested from starters as being a new generation. I'm not a professional yeast wrangler or anything, but one of the reasons you make a starter is so the yeasts replicate and grow cells to your desired pitching cell count.
Since they've replicated I consider that to be a new generation.
My terms may be wrong, but that's my line of thinking.
Excellent idea on making 10 stocks from the initial yeast. I need to start doing that. Well, actually, I need to start freezing mine. Just haven't gone down that rabbit hole yet of figuring out how to do it. I've glanced through some articles on it. Just haven't gotten down to brass tacks yet. I think the one thing I worried about is the whole thing I've read about freezers defrosting cycle. I think some people keep the frozen yeasts in a small styrofoam box or something with an ice pack in the fridge? Is that necessary?Yeast growth is still yeast growth. Mutations occur from mistakes in replicating DNA. Only if there is some inherent benefit to that mutation will that strain out populate the "original" strain.
From a selective perspective, I would expect continued propagation of the same strain of yeast in starter wort to eventually (this is the key, how many growth cycles is likely strain dependent) adapt it to lower sugar conditions. I don't know if this would be manifested in lower attenuation in an actual beer though? Maybe just more stress?
Anyways, I typically make 10 stocks from a first propagation (stored in the freezer with 20% glycerol), use all of those up and then make another 10 on the last one. The BEST way (and what I would imagine the commercial labs do), is to keep 2 mother stocks (one as a back up) that are only used to streak out the yeast for growth. This way, you always have a generation zero banked because you aren't "using up" the original stock.
For those interested....
Yeast Bay sells a blend of these 2 yeasts called "Funkytown".
This is actually a genetic hybrid, not a yeast blend. I created the hybrid by rare mating a uracil auxotroph of Conan with a lysine auxotroph of WLP644. Hybrids were isolated by their ability to grow on media lacking uracil and lysine (which the parent auxotrophs can't grow on), and their hybrid status was further confirmed with interdelta-PCR.
...1
The strains that I'm offer to send is H1 (the original hybrid) and H1/C4 (the fastest fermenting meiotic segregant of H1, which also finished with quite a high pH)
This thread, however, is about GENETIC HYBRIDs of the two.
I don't bottle much anymore aside from brews to cellar. So, no, I haven't, but there's multiple accounts of it happening.
This is actually a genetic hybrid, not a yeast blend. I created the hybrid by rare mating a uracil auxotroph of Conan with a lysine auxotroph of WLP644. Hybrids were isolated by their ability to grow on media lacking uracil and lysine (which the parent auxotrophs can't grow on), and their hybrid status was further confirmed with interdelta-PCR.
International shipping is not a problem! Since I'm shipping only small volumes (2 ml of slurry in a microtube), worldwide shipping is 2.80€. I don't have the possibility to offer larger volumes of slurry since a) there has been a lot of interest, and b) shipping gets really expensive.
The strains that I'm offer to send is H1 (the original hybrid) and H1/C4 (the fastest fermenting meiotic segregant of H1, which also finished with quite a high pH)
Do you detail your process somewhere, and where you got your stuff? I'd love to make my own yeast crosses.
Edit: to clarify, I saw the blog entry, but I'm not sure how exactly you create auxotrophs?
I used the same process for creating these Conan x WLP644 hybrids, as when I made these lager yeast hybrids:
http://link.springer.com/article/10.1007/s10295-015-1597-6
The auxotrophs were not created, but rather selected from a population of the parent strains. Spontaneous auxotrophic mutants (both lys- and ura-) exist at a frequency of about 1 - 10 * 10^-7 cells, and these can be isolated by spreading out a suspension of the parent strains on media containing α-aminoadipic (for lys- isolates) and 5-fluoroorotic acid (for ura- isolates).
Thanks, I'll look into that.
Next question would be why? You said you preferred rare mating to spore mating, but I didn't quite understand why? Did you specifically wish for polyploid hybrids instead of diploid crosses, for some reason? I know for plants polyploids are often more vigorous than diploids, was this the point? Or did you simply want the hybrid to have all of both traits, instead of just a random mix of half and half? Greater odds of heterosis effect?
Also, are those substances that laymen could get their hands on? Or should I stick with spore mating?
Here's the thread
https://www.homebrewtalk.com/showthread.php?t=597557
On the last page, one Brewer notes 1318 not being an issue, but Conan is.
It's happening VERY fast, but seems to be only to warm beer(bottle conditioned). There's pics as well.
Rather interesting.
Is the original page with the info of the yeasts down now? My (work) browser just blocked it saying license expired, despite the fact that work has never blocked this site before. Any thoughts? I wanted to re-read some stuff on there.
Is the original page with the info of the yeasts down now? My (work) browser just blocked it saying license expired, despite the fact that work has never blocked this site before. Any thoughts? I wanted to re-read some stuff on there.
Got it now! Thanks. Stupid government computers...If you are talking about my blog, it should be working 😊
If you are talking about my blog, it should be working 😊
Hey pal, you planning on making a new batch to mail out soon? 😎
Just got done brewing a NE IPA that I'm going to ferment with 3rd generation Conan. I don't bottle but I'll post if anything weird happens.
Shout out to TravelingLight for hooking me up with the F1 and F1/C4 strains. Here is my rye, NEIPA fermented with the F1 that I dyed pink with beet puree. It looks and tastes like grapefruit juice. Here it is pictured before carbing.View attachment 400119
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