First time building a starter - does this look OK ?

[The-Engineer-That-Brews]

Morning all -

I pitched this yesterday evening with fresh WLP800, so it's now had 16 hours on the stirplate at room temp with air bubbled into it.

Does it look OK and is it ready for me to add fresh wort (to take it from 1 to 3L) ?

Its appearance has changed and it smells nice and yeasty - but according to the refractometer the SG is the same and I was expecting to see a bit more of a head on it...

(L: freshly pitched; R: +16 hrs)

 

[Oneflewover]

Morning all -

I pitched this yesterday evening with fresh WLP800, so it's now had 16 hours on the stirplate at room temp with air bubbled into it.

Does it look OK and is it ready for me to add fresh wort (to take it from 1 to 3L) ?

Its appearance has changed and it smells nice and yeasty - but according to the refractometer the SG is the same and I was expecting to see a bit more of a head on it...

(L: freshly pitched; R: +16 hrs)
View attachment 47255 View attachment 47256

Looks good to me, gone nice and creamy

 

[The-Engineer-That-Brews]

Looks good to me, gone nice and creamy

Thanks! Phew. Good to add the next amount of wort then?

 

[DocAnna]

Purely from my experience with the stir plate, there's no krausen or head as it is dissipated with the stirring. The Right side picture looks spot on for the yeast having had a fun time in there .

 

[The-Engineer-That-Brews]

Note to self: don't try to be clever and weigh out spray-dried DME straight into a pan of boiling water - the steam makes it stick to the spoon like some kind of insane snowball...

 

[cushyno]

If the SG has not shifted much, wait until it has dropped to your expected FG before stepping up. If you are chilling and decanting, do so before the step up. If you are adding more wort just to up the volume try to ensure the combined liquid of first (supernatant) and second (fresh wort) are in the region of 1.038 after combining. It doesn't do any harm to go lower which will stress the yeast less but you also won't grow as many cells.

 

[The-Engineer-That-Brews]

If the SG has not shifted much, wait until it has dropped to your expected FG before stepping up. If you are chilling and decanting, do so before the step up. If you are adding more wort just to up the volume try to ensure the combined liquid of first (supernatant) and second (fresh wort) are in the region of 1.038 after combining. It doesn't do any harm to go lower which will stress the yeast less but you also won't grow as many cells.

Thanks mate - this is all new to me, so all guidance appreciated.

The reason I'm adding fresh wort at this point is to increase the cell count... I'm doing 30L of lager (1.051) so I'm told that I need about 600bn cells; so if I'm using the online calc correctly, I should have about 200bn cells at this point, then around 600 after a 'step' to 3L (i.e. adding a further 2L of fresh wort). Does that sound about right?

I wasn't planning to chill and decant at this stage because my vessel is large enough (5L) that I don't need to. However I thought I might chill/decant before pitching into the brew so that I'm not adding too much volume.

When you say "dropped to your expected FG" I'm not sure what FG I should use... according to the refractometer it was initially 1039 (100g DME in 1L) and it's now down to about 1037 ??

 

[Buffers brewery]

according to the refractometer it was initially 1039 (100g DME in 1L) and it's now down to about 1037

Do you need to apply a correction to the last refractometer reading?

 

[The-Engineer-That-Brews]

Do you need to apply a correction to the last refractometer reading?

Maybe, if the alcohol has gone up - my limited understanding is that the yeast should be doing aerobic reproduction at the moment rather than fermentation ... but to be honest this is all new to me :-)

 

[Buffers brewery]

Me too. Just assumed if you were expecting a drop in SG that meant alcohol . What do I know

 

[cushyno]

The terminal drop in gravity will be gravity of the original wort - the attenuation of the yeast.

So, if you used 100g dme in 1L, that's about 1.038 (ish). If your yeast attenuation is say, 76%, that means terminal gravity is 38* (1-0.76) = 9, or 1.009. so long as you're somewhere near (1.009-1.015) you're probably ready for the next step.

Hope that helps.

 

[The-Engineer-That-Brews]

The terminal drop in gravity will be gravity of the original wort - the attenuation of the yeast.

So, if you used 100g dme in 1L, that's about 1.038 (ish). If your yeast attenuation is say, 76%, that means terminal gravity is 38* (1-0.76) = 9, or 1.009. so long as you're somewhere near (1.009-1.015) you're probably ready for the next step.

Hope that helps.

Helps a lot - thanks. OK, well in that case I made the addition too early but at least I'll know next time... Fortunately it seems to be nice and active anyhow, so I'll just keep an eye on it and see what happens

 

[cushyno]

You'll definitely have some active and healthy yeast which is most important.

 

[The-Engineer-That-Brews]

You'll definitely have some active and healthy yeast which is most important.

5hrs after adding more wort - there's certainly a decent amount of froth showing now... mind you, with 3x the volume and the same surface area I suppose that's early surprising, is it (!)

 

[cushyno]

That's a mighty starter!

 

[The-Engineer-That-Brews]

Now wondering ...
(a) how long the growth phase will continue
(b) how long it will take to flocculate and precipitate out, once I cold crash it
(c) whether I'll be checking away all the active yeast cells in the clear 'beer', and jpitching the sediment which is just all the dead cells

Aaaargh the stress is killing me....

 

[The-Engineer-That-Brews]

That's a mighty starter!

Yes - it seems like an insane volume to me... but there seemed to be broad consensus that I need to pitch with upwards of 500bn cells, and according to the calculators this seemed like the way to do it

 

[cushyno]

Trouble with all this rule of thumb and "that looks about right", as an engineer it messes with your head which wants precision
I know. I used to be a mechanical engineer.
You gotta get used to it with yeast it seems. Don't sweat the absolute precision. If you've seen some of the braukaiser experiments on which some of the figures are based, for homebrewers I reckon the margin of error is pretty high so there must be a tolerance of maybe 20% either way. If you underpitch you can still produce good, nay, great beer if the yeast is healthy. So many factors such as wort fermentability, temperature control, nutrients, pitching temperature of both wort and yeast all play a part.

Last year I did a Munich Helles built up to 2.5l from from 1/2 pack of MJ M84 dried yeast. Wisdom says I should have used liquid yeast if going to all that trouble. The Helles turned out great. For my boho pils today I'm pitching 1.5 packs of M84 and crossing my fingers. I didn't plan ahead and wanted to brew on the spur of the moment, but I'm guessing it will be enough and it probably will.

Yours will be fine.

 

[cushyno]

Wish me luck...

 

[Oneflewover]

Now wondering ...
(a) how long the growth phase will continue
(b) how long it will take to flocculate and precipitate out, once I cold crash it
(c) whether I'll be checking away all the active yeast cells in the clear 'beer', and jpitching the sediment which is just all the dead cells

Aaaargh the stress is killing me....

Chuck it all in