Is this normal?

[RishoBrew]

Last night I've made a starter for this Imperial Pub strain, like I did dozens of time before. Except I forgot to add yeast nutrient. This morning I noticed it had a cottage cheese texture and dark specks. Is this normal?
Here is link to short clip that shows what I'm referring to.


This picture shows the bottom of the E/M flask.

 

[myndflyte]

Was there burnt stuff at the bottom when you used it?

 

[RishoBrew]

Was there burnt stuff at the bottom when you used it?

No there wasn't, I used a regular DME and I did't burn.

 

[day_trippr]

wrt the "cottage cheese", I wonder if this is Imperial's version of wlp002?
No idea wth is going on with all that debris on the bottom...

Cheers!

 

[OnePlate]

I've heard Imperial Pub and WLP002 are similar strains with Pub being the closest to the actual Fuller's yeast, so the cottage cheese looking flocculation is normal. But the flecks look like scorched extract to me.

 

[RishoBrew]

But the flecks look like scorched extract to me.

Any harm with that, if I pitch it? The quantity is minuscule.

 

[IslandLizard]

Any harm with that, if I pitch it? The quantity is minuscule.

Nah!

 

[IslandLizard]

Given the small starter volume (<500 ml?) and ~200 billion cells in the yeast pack, I would call this a wake-up (vitality) starter. With such a high cell density I doubt there's much or any cell growth, and no wonder it's dropping out like crazy. Yup, pitch as is, maybe save some out for a next batch, and again, and again...

 

[RishoBrew]

Given the small starter volume (<500 ml?) and ~200 billion cells in the yeast pack...

So the born date of this Pub strain was June 12, 2019. I bought in Aug 15, kept in the fridge till 23rd. The Morebeer.com yeast pitch calculator suggested viability of 47.3% with 94.6 bil. cells. So I've concocted a 1L starter which I normally spin for 36 hours. Today is Sunday and the soonest I will be able to brew is next Saturday. It definitely seem like a lot of yeast for 5-7 gallon of wort tho.

 

[IslandLizard]

So the born date of this Pub strain was June 12, 2019. I bought in Aug 15, kept in the fridge till 23rd. The Morebeer.com yeast pitch calculator suggested viability of 47.3% with 94.6 bil. cells. So I've concocted a 1L starter which I normally spin for 36 hours. Today is Sunday and the soonest I will be able to brew is next Saturday. It definitely seem like a lot of yeast for 5-7 gallon of wort tho.

I mostly use this calc: BrewUnited's Yeast Calculator

Viability is estimated at ~65% after only 2 months, but a lot depends on the way she is packaged (WLP sleeves fare much better than anything else, >90% after 3 months) and handling/transport (high temps).

OK, a liter is better, it looked less than that to me. 2 liter would be preferred with such a large initial count, plus you can save some out.

 

[RishoBrew]

Thanks for all your replies. I've reached out to Imperial and this morning I got a reply, so figured I'd share the knowledge.

"That is super normal for the A09 Pub strain- it's highly flocculent and develops the chunky, cottage cheese texture quite easily. The black specks are just protein and nothing to worry about.


I would pull it off the stir plate, the starter look to be done though definitely double check by taking a gravity reading. If it's done, too much oxygen at this stage is actually detrimental to yeast health. "

 

[day_trippr]