rehydration necessary for s-04?

I'm a relative newbie to all grain. Eight batches under my belt. Plan for this weekend is to brew a 3 gallon batch of Russian Imperial Stout. Going with S-04 for yeast. Two packs based on Beersmith calcs. I have not used dry yeast previously. I've been reading about rehydrating in Palmer's book. Given that I'm cooking up a high gravity brew, is rehydration recommended?

there are two different schools of thought on this. Some are adament about rehydrating, others say its not necessary at all. Even some dry packets say there is no need to rehydrate so that pushes people in that direction too.

Personally i believe in the school of rehydration. it doesn't hurt anything to rehydrate as long as u prepare it properly. And by that i mean using sterile water and containers and use good sanitation practices.

Every once in awhile u may get a bad batch of yeast (or one with low viability). This is the best way to insure that the yeast u are dumping in ur FV are awake and their membranes are ready to process all the different sugars.

I've always been a strong believer in rehydrating. have made batches without doing so but usually make the extra effort. Should be fine either way.

the packages tell you to either pitch as is, or rehydrate, depending on manufacturer. i go with what they say, even though i've never noticed a difference, but they're the experts on their own yeast. safbrew says to pitch directly. lallemand says to rehydrate

I never rehydrate dry yeast, and I often use US-04 / 05. on those beers the gravity is around 1.060 or less. I have had no issues or problems / off flavors.
People use different methods, try it and see what works for you.

Thanks to all for the input. Today was brew day. Did not make the starter, but all is well so far. The S-04 kicked off in the primary in approx four hours. Won't drink this brew until Xmas 2013.

Put me in the rehydration camp. YMMV.

Edit: looks like I was a little late.

I rehydrate every dry eyast I've used and they can easily finish a 1.07 beer with no issue. Not sure if the same would happen if I just sprinkled it in

I used us-05 almost exclusively for years.

I started to rehydrate the yeast but stopped after a while because there was no noticeable difference what so ever.

That's my experience though. YMMV

Have been using Ferments yeasts since 1998, both home and commercial (for 2 years prior to that I was using Nottingham commercially). I see no need for rehydration. Around that time some colleagues and myself did a blind test comparing hydration vs non hydration and saw no appreciable benefit.

When using S04 at home, I dump the pack into the fermenter before my wort goes in rather than sprinkling dry yeast on top. It does seem to make a difference. At the commercial level I pitch the yeast dry before I transfer wort into the fermented, same effect. The yeast gets churned up and everything is go. Typical start time is 8 hours.

wailingguitar said:

When using S04 at home, I dump the pack into the fermenter before my wort goes in rather than sprinkling dry yeast on top. It does seem to make a difference.

Click to expand...

Sorry to hijack the thread, but just out of curiosity, what difference did you notice doing this?

I've noticed a small difference on rehydration. Then again, since I am typically doing fairly small batches in the 2.5-3.5G size until fairly recently (when I've been doing more 4-5G batches), the fact that I've been direct pitching an entire packet of dry yeast, versus rehydrating probably didn't make much difference.

At 2.5G of RIS, I would highly recommend rehydrating. Supposedly direct pitching leads to 50% cell death initially. I'd say that number is BS, in that since the death is caused by shock from not controlling what is taken across the cell membrane at first, then the gravity of the worth has GOT to influence the cell death %'s, which means higher gravity is likely to lead to more initial cell death if you don't rehydrate.

Frankly rehydrating is minimal extra effort, so I have been the last few months.

I like to rehydrate by boiling a 1/2 cup of tap water in a saucepan for 5 minutes at the beginning of my 60minute boil. i set it aside to cool and by the time the boil is finished, it's cooled to about 80F, ready to hydrate while I am chilling the wort.

It's very little extra effort, and it's nice to know I'm not killing half of my yeast when I pitch it.

firerat said:

Sorry to hijack the thread, but just out of curiosity, what difference did you notice doing this?

Click to expand...

Shorter lag time as opposed to sprinkling over the top of the wort. My assumption is that the yeast gets hydrated quicker and is spread evenly through the wort by the churning action.