Yeast starter

[steve123]

After some advice on a yeast starter, I’m making a 40l batch using white labs WLP550, aiming for an abv of about 8, so doing a 2 stage starter. I’ve done the first one drained off the wort and added more water and dme after boiling and cooling it. I started the second starter about 3 today, I made 2.2 L and added it to the Demi john (just under 5L) put on the stir plate, and by 5pm it was foaming over. I turned off the stir plate and cleaned up the mess.

Should I just leave the stir plate off or turn it back on later. Given the high level of activity will it just sort itself out or will there be value turning the stir plate back on.

 

[Hoppyland]

Well, this is not a process I normally use.
But.... If I was you, and you have 5l of starter fermenting vigorously, then I'd just pitch it straight away into your 40l of wort. I can't see any merit in waiting: if your wort is ready & waiting then it can only serve as a medium for spoilage organisms if it doesn't start fermenting, and your vigorous starter will ensure a very rapid start to fermentation.

 

[steve123]

Thanks for your reply, not made the beer yet was planning ahead, going to make it Monday. Was also going to do a third stage to build the yeast so I could store some for future use! I was following the brewers friend yeast calculator and was planning to do a third stage and add another 4l! However given that it’s over flowing after just over 2 l thinking twice about it!

 

[Hoppyland]

With brewing, there are always several ways to go about things. For me, I wouldn't try to build a starter so that it can be spread over several brews. But, the main reason why I wouldn't is because I nearly always use a secondary fermentor, and this makes it so easy to harvest vigorous yeast for re-pitching when I do the initial transfer.

 

[Zephyr259]

Yeah i wouldn't do a 4L starter in a 1 gallon demijohn, that's some crazy yeast that over flowed from 2.2L! I overbuild and save my starters between batches too, in cases like this I'll save it from the first starter to keep the second volume lower since I only have a 2L flask.

Turning the stir plate back on will keep the dissolved CO2 to a minimum and reintroduce oxygen (in theory) so there is benefit to it but given I'm 2 days after you posted it's kinda irrelevant now. How are things looking?

 

[steve123]

I turned the stir plate off to try and get it to settle down, there was still some foam that over flowed but then it came down by the morning, it may of settled down as the temperature dropped to 15, the stir plate gives off heat and managers to maintain temperature. I then turned it back on again and again it built up to the head with a slight overflow, but I just left it on and when I checked it this morning all the foam has gone so I’ve now put it in the fridge.
So now deciding whether to go for the third stage and save some, and if so how much wort to add. Or just to stick with what I have and maybe siphon a small quantity off to build up next time

 

[Zephyr259]

Ah, cool cool. This website should help you work out how many cells you've grown up and how to overbuild in future. I wondered if you were already using something similar as a 4L starter with a stir plate is a huge amount of yeast to need.

 

[steve123]

Thanks for this, I will take a look.

I don’t think I will do a third stage as the link you sent suggests that inoculation rate bewteen 25 and 100 million should be done and unless i pitch 7 L I won’t get that. I think I need to start with a smaller starter and build up next time rather than 3L then 2.2L I will go 1.5 L and 3L