Double Batch Fermentation-Fermentis Yeast

[alehousebrewing]

I am planning on doing double batch fermentation on my 1bbl brew house over 2 days. I was wondering how much yeast one should add to the first bbl. I have taken a look at a couple of pitch calculators which show that a rate for a 1bbl would work for a 2 bbl fermentation batch (at the recommended rate by Fermentis S-05). My pitch rate is going to be about 12.5mil/mL.

Does anyone have any experience with this? Do you add more yeast for the first batch or any during the seconds way to the fermenter?

Any help would be killer.

Thanks

[kugeman]

Add all the yeast during the first brew and oxygenate the first brew. Don't add more yeast and don't oxygenate the second brew if you're brewing on back to back days.

If you double brew in 1 day then you can go ahead and oxygenate the 2nd brew length.

[alehousebrewing]

thanks for the reply. For the yeast pitch rate, do you add yeast for 2 bbls or just 1. The yeast calculator showed that if you pitch for 1 bbl, there should be enough cells for the full 2 bbl batch by the next dayish.

[kugeman]

I can't say I have a "technically informed" answer for you, but when I double batch (on back to back days) I pitch 1 1/2 times the yeast for the first batch. So basically I'm going half way between what I'd pitch for a single vs. double batch. I figure that way I'm not crazy over pitching the first brew length.

But if this is your first pitch with dry yeast I would probably go ahead and pitch the entire 2 bbl amount. Assuming you're just pitching dry right into the oxygenated wort it's going to take a few hours (maybe as many as 12) to get going. So by the time you knock out the 2nd brew length you wouldn't have had all that much yeast reproduction in the tank.

You won't really know what's going to happen until you give it a try.

[timbro81]

In my experience I would pitch a one barrel amount of yeast if it is being spread out over 24 hours. A two barrel amount of yeast if you can get it done in one day. As mentioned above, I would not oxygenate the wort on the second day. Good luck!

[CharlosCarlies]

I know there are a lot of threads on double batching, but since we use Fermentis yeast as well in one of our core beers I figured I'd bump this thread just to see if there are any additional concerns when using dry yeast.

We're basically stuck knocking out 24 hrs apart, so my thoughts are to pitch enough yeast for the first batch as usual (we don't add oxygen on the first pitch of dry yeast...no issues), then add oxygen to the second knock-out to keep the yeast in growth phase to get to the proper cell count for the double batch.

Thoughts? As mentioned, I know there's been a ton of discussion on this but still haven't seen much consensus on the why's and how's of what's going on with the yeast.