Unexpectedly vigorous fermentation

[ErikRobers]

... or at least it seems vigorous.

Prior to using a swamp cooler for my primary fermentation, I would pitch my yeast (2-pks safale s-04) and leave my carboy in my closet at 68 degrees with a blowoff hose leading to a gallon spring water jug half full of water/iodine mix. I would typically have vigorous fermentation and need to change out jugs after 12 hours or so. I recently brewed a batch I expect to be around 7.2% ABV (previous batches in question were the same recipe), pitched two packs of safale s-04, and placed it into the cooler with water about two inches shy of the wort level. The water temp has been kept at 62-63 degrees, and now 24 hours later the fermentation has been vigorous enough that I needed to change out jugs... albeit, the foam was not nearly as dense as when I kept it at 68 degrees.

Is 62-63 degrees still too warm? Is the nature of this yeast, and the fact that I used two yeast packs such that this level of fermentation isn't as surprising as I found it to be?

 

[Calder]

Cool temps do not prevent blow-offs. The yeast is still working, you are just taking heat out more efficiently.

Yes, lower temps would generally lead to less violent ferments, but I'm not sure it would be enough to notice.

I don't use dry yeasts, but for a roughly 1.070 wort, I would have thought 1 pack would have been OK. I'm sure someone will set me straight if this is bad information.

 

[ErikRobers]

Cool temps do not prevent blow-offs. The yeast is still working, you are just taking heat out more efficiently.

Yes, lower temps would generally lead to less violent ferments, but I'm not sure it would be enough to notice.

I don't use dry yeasts, but for a roughly 1.070 wort, I would have thought 1 pack would have been OK. I'm sure someone will set me straight if this is bad information.

Okay, good to know. I guess I just figured that the lower temps would slow the activity of the yeast such that there would be little to no blow-offing going on... which is really the case, all things considered to the previous batches.

I was going to use Wyeast 1099 (Whitbread), but the store sold me a dead pack. I had the two s-04's in the fridge, found out that s-04 is a Whitbread strain, and so I felt it would be a suitable substitute. Being as I'd have needed a starter, I figured it'd be best to use a little too much yeast than a little too little.

 

[kh54s10]

Cool temps do not prevent blow-offs. The yeast is still working, you are just taking heat out more efficiently.

Yes, lower temps would generally lead to less violent ferments, but I'm not sure it would be enough to notice.

I don't use dry yeasts, but for a roughly 1.070 wort, I would have thought 1 pack would have been OK. I'm sure someone will set me straight if this is bad information.

I would say that one pack of dry yeast is close to enough for a 1.070 wort. 2 packs will start fermentation sooner but not necessarily more vigorous..

I always start every fermentation with a blow off tube installed. How much blow off I get does not concern me...

Clean up and proceed.....

 

[day_trippr]

I disagree with the temperature control vs blow-off thing. I see a solid relationship between running temperature and the level of yeast activity, and so all of my fermentations are temperature controlled.

And S04 is a beast. Sans solid temperature control any violence with that yeast would not surprise me at all.

As for the pitch, I've always used just one pack for ~5.5g of up to ~95 point wort (think chewy stouts) and without temperature control that can easily go nuclear. Two packs is solid overkill, imo...

Cheers!

 

[ErikRobers]

I appreciate all the feedback guys, I wasn't aware that s-04 was such an active yeast. I looked in on it this morning and it looks like it stopped pushing kraussen through the blowoff overnight, and there was never any major blowoff like when I kept it at 68. Overall, this portion of the fermentation was much less violent and I can see that the buildup was indeed much slower and that fermentation is going to go on much longer than in the past. Thanks again.