Review my yeast harvesting process?

[luckybeagle]

I brewed a dry Irish stout that I now have bottled (and drank) without much thought. On my last bottle, I decided I might need some of the yeast for my next beer, so I did the following:

1. Cracked the beer and poured 10 of 12 oz into my pint glass. Drank it.
2. Swirled the last 2 oz to break free the yeast sediment on the bottom of the bottle into suspension
3. Poured that into a 1 quart plastic milk jug that I had cleaned out well and let sit with starsan + water solution
4. Added simple wort (25g DME boiled for 20 minutes with 8 oz water). Gave it a good shake/stir whenever I passed by the kitchen
5. Let sit for 24 hrs before adding 25g DME and 8oz boiled water)
6. Let sit for 24 hrs before adding additional 25g DME and 8oz boiled water.

It seems as though it fermented out after 24 hours of each wort stepping.

I'm getting ready to cold crash and decant off the liquid before adding a full liter of starter wort. Taste tests seem normal, a nice clean typical Irish flavor (fruity, dry, no off-flavors). Should I keep following this process until I'm up to a 2L starter, which is what my next beer calls for? Did I make any critical mistakes?

 

[luckybeagle]

to the top please

 

[day_trippr]

Starter gravity was a bit heavy for the first step - when resurrecting bottle dregs I usually start with 100ml of 1.010 wort - but aside from that first step if you've made it this far I'd say keep stepping until you have a pitchable volume of yeast.

I'd be cautious about assuming the next step will be the last - calculators generally assume certain cell counts from commercially packaged strains so you started from a level that most calculators don't handle well...

Cheers!

 

[luckybeagle]

Starter gravity was a bit heavy for the first step - when resurrecting bottle dregs I usually start with 100ml of 1.010 wort - but aside from that first step if you've made it this far I'd say keep stepping until you have a pitchable volume of yeast.

I'd be cautious about assuming the next step will be the last - calculators generally assume certain cell counts from commercially packaged strains so you started from a level that most calculators don't handle well...

Cheers!

Thanks kindly!

I'm up to about 2L on this starter now and it's bubbling away fantastically. Each step has gotten to bubbling quicker and more vigorously than the previous one. There was definitely a lag with the first and second steps. You're probably right that the starter wort was too strong. Note taken for next time

Can't wait to put it to use on either an IRA or a Scottish/Scotch ale!

So many beers, so little time.

 

[IslandLizard]

Each time you add a fresh 8 oz starter dose (SG ~1.037) to the ongoing starter it gets diluted more and more. IOW, your initial starter gravity keeps dropping.

Instead, once you've got the yeast culture established (+1 @day_trippr) I would target bringing the gravity of the whole starter to 1.037 with each addition, using stronger wort.
That way you should get maximum growth all the way. Then once you've got a liter, cold crash, decant and add 2 liters of 1.037 wort to obtain a pitchable amount and some to spare for a next starter.

Make sure to add some nutrients to your starter wort (DAP/Urea/Mg/Zn). I mix my own and add 1/4 tsp per 2 liter.

 

[IslandLizard]

So many beers, so little time.

Best is to overbuild all your starters from the get go, and save some out for the next round and so on. Building yeast pitches from dregs is not the optimal route, it may have mutated. I ended up with some really foggy ESBs that way.

 

[Beer-lord]

Best is to overbuild all your starters from the get go, and save some out for the next round and so on. Building yeast pitches from dregs is not the optimal route, it may have mutated. I ended up with some really foggy ESBs that way.

+1 for overbuilding your starters.
This has worked extremely well for me for 4 years now.

 

[luckybeagle]

Thanks kindly. Since it’s from a beer I brewed, should I still give it a go in my next beer—an Irish red ale? I don’t mind cloudiness as long as it doesn’t come out tasting like vinegar or cardboard [emoji38]

 

[IslandLizard]

Thanks kindly. Since it’s from a beer I brewed, should I still give it a go in my next beer—an Irish red ale? I don’t mind cloudiness as long as it doesn’t come out tasting like vinegar or cardboard [emoji38]

Taste some of the starter beer from the flask (use good sanitation, as usual). If it tastes "good" not sour or putrid, the yeast is probably fine to use.

When are you brewing? Is there time to cold crash it for a few days to get rid of the starter beer?
Definitely save some out for a next starter, and so on! Yeast gives on giving (within certain limits, sadly).

 

[luckybeagle]

Taste some of the starter beer from the flask (use good sanitation, as usual). If it tastes "good" not sour or putrid, the yeast is probably fine to use.

When are you brewing? Is there time to cold crash it for a few days to get rid of the starter beer?
Definitely save some out for a next starter, and so on! Yeast gives on giving (within certain limits, sadly).

I’ll probably brew over the weekend and currently have it crashing in the fridge! I’ll decant it tonight and do one more liter. I could push brew day out, but what do you think about pitching at high Krausen at 1 liter (5% of volume in fermenter) instead of pitching slurry? Bad idea for a lower ABV (5.5%) beer?

 

[IslandLizard]

I’ll probably brew over the weekend and currently have it crashing in the fridge! I’ll decant it tonight and do one more liter. I could push brew day out, but what do you think about pitching at high Krausen at 1 liter (5% of volume in fermenter) instead of pitching slurry? Bad idea for a lower ABV (5.5%) beer?

Sure, pitch your freshly made 1 liter* at high krausen/high activity. No need to cold crash, there is not enough time. When pitching make sure the yeast and wort are close in temp (10F maximum, 5F best).
Aerate or oxygenate.

* Perhaps make 1.5 liter and retain 1/2 liter for next time?

Don't forget to save some out for next time!

 

[luckybeagle]

Sure, pitch your freshly made 1 liter* at high krausen/high activity. No need to cold crash, there is not enough time. When pitching make sure the yeast and wort are close in temp (10F maximum, 5F best).
Aerate or oxygenate.

* Perhaps make 1.5 liter and retain 1/2 liter for next time?

Don't forget to save some out for next time!

Will do!!

Glad to hear all that, too. Thanks for all the help.

Man, I've got the brewing bug bad. Great hobby, and great support on this forum

 

[IslandLizard]

Don't forget to save some out for next time!

Quoting myself.
I can't say this often enough, it's so much easier and better to propagate yeast from a clean starter than from a used slurry or bottle dregs. You know this first hand now.

Put a piece of tape around the 500 ml level or so as a reminder...
It also keeps your stir bean out of your beer. You can let that leftover starter spin out another day or 2 until it's done.

 

[luckybeagle]

That makes sense. But I am curious why some people really like dumping their next batch of wort on top of a yeast cake that just finished fermenting a beer if using fresh is better? Is that situation an exception since you're tasking a recently active, existing population of yeast cells rather than trying to multiply a small culture many times over?

 

[IslandLizard]

That makes sense. But I am curious why some people really like dumping their next batch of wort on top of a yeast cake that just finished fermenting a beer if using fresh is better? Is that situation an exception since you're tasking a recently active, existing population of yeast cells rather than trying to multiply a small culture many times over?

Well... One really shouldn't repitch yeast cakes from high gravity beers, or from beers with substantial differences in color or hop content.

For example a gravity of 1.060-1.070 beer can still yield a good repitch-able yeast cake. I'm not alone repitching those many times and never heard or read complaints. But after 6-10 rounds it may become a problem, depending on how it was handled.

Now repitching a (partial) cake from a 1.080 beer or above, no! Using a (partial) cake from a NEIPA for a Blonde, Golden Ale, an Amber or a Stout, etc., no!

I've repitched (partial) NEIPA cakes into other NEIPAs, dry hop trub and all, many times. I may make a vitality starter of it right before re-pitching if the cake is older than say 4-6 weeks. Many yeasts actually perform better after a few rounds (e.g., Conan), due to adaptation to the beers they fermented and the environment. That's how "house yeasts" become in breweries.

A yeast cake contains 4-5 times the amount of cells that were pitched. So pitching on top of a whole existing cake may be a gross overpitch, that's not good. Best is to only use a part (1/5-1/3) of it depending on estimated count and age and cells needed for the new beer. 2/3-4/5 of that (partial) cake consists of young, rather unstressed cells, so it's mostly good viable yeast.

But there are limits to how often yeast can be repitched. Fresh yeast is better in many aspects. It's purer, cleaner, containing none or very few contaminations, bacteria, wild, or other yeasts and microorganisms and suffered fewer mutations and causes of other potential problems.
New, pitchable yeast amounts can be grown from small colonies, say after a small vial of them had been stored frozen for keeps for a few years. Similar to your dregs, regrowing them takes time.