Faster fermentation with not rehydrating?

I have pitched dry yeast and I have rehydrated yeast. I don't take notes while brewing, so I can't remember if I usually get fermentation to start quicker with dry or rehydrating yeast. I am about to do N. Brewer's Ace of Spades Black IPA with an OG of 1.068. Their brewers told me via e-mail to simply sprinkle the wort on top and I should expect fermentation to start within 12 hours. I do know the last three batches I did, I rehydrated and my airlock (which I know is not a sure sign of fermentation) did not bubble until about 20 hours after pitching. N. Brewer itself has a video on its own website promoting the practice of rehydrating and when I asked about that, I was told in the e-mail that there were possible mistakes people make during that process that could cause more harm than good. However, it's a pretty basic process and I'm confident I follow standard practices to rehydrate my yeast. So, in short, if getting the wort to ferment quicker with simple sprinkling on top, is that the way you guys go? Or, do you think it's always best to rehydrate? Is getting the beer to ferment the quickest always best?

 

I'm no expert but I think rehydration is best because the yeast cannot control what their cells take up when coming directly from a dehydrated state. They need to be awakened slowly with water first in order to be most productive. As far as fast fermentation goes the yeast need to have a lag phase in order to build up their cell walls and have healthy reproduction. A very fast lag phase could mean they are not reproducing very much. Not sure what that does to the finished beer but I think a lag phase between 12-18 hours is best.

 

I've just listened to a podcast on the subject that did experiments with rehydrated and un-rehydrated yeast and it seemed that the un-rehydrated (direct sprinkle on) method worked better than expected and indeed outperformed the rehydrated yeast.

Encouraged by this, I tried this with my new batch of Weiss with some SAF 05.

However, there was problem. Because I had aerated my wort with oxygen, a thick head of foam had formed on the surface which did not allow me to sprinkle the yeast directly on the wort. I did the best I could by pushing the foam aside with a spoon but I could only really stir the yeast into the wort - as opposed to letting it lay on the top of the wort and sink in by itself.

Seemed to take off OK at around 18 hours.

I wonder if this inability to sprinkle onto the surface of the wort is a problem of if just stirring into the wort is OK ?

 

I have both dry pitched and rehydrated. I don't know which started quicker because they all started during the night. But it seems that sprinkling on would have to hydrate first, then start fermentation, so it should be slower.

That said, which starts faster is really not a concern to me. I want what is better. You can make yeast start and finish very fast if you wanted to = pitch way too much yeast and ferment really warm. It will go fast but you probably will not like the results.

 

You can shake the wort up after adding the yeast, as well.

I have used rehydrated and seen krausen at 14 hours.

 

Wheelspin - interesting about the sprinkled on dry yeast maybe not getting in direct contact with the wort due to the foam from aeration. Since I just got my new aeration setup up and running again (had to get a new filter as it was clogged which didn't allow for ample bubbling from the air stone) I certainly will be hoping for some foam from the aeration prior to pitching. And, I too have read on lots of posts on here about the potential of killing 50% of the yeast cells if you sprinkle it right on top. HOwever, I think I also read a post from Revvy on here where he said he just sprinkles it on. I guess I'll do one more batch of rehydration and see what happens. With the OG of this beer, the idea of losing a lot of cells is not appealing. I just found it odd that a N. Brewer employee went against what the N. Brewer website said. My guess is that some of their customers don't rehydrate properly (maybe don't use previously boiled water or don't have the yeast slurry within 10 degrees of the wort temp) so when some customers try to rehydrate they do more harm than good. My guess is that if you can do it correctly, it's better than not, but at the end of the day the differences might be negligible.

 

My experience is the same, although temperature may have had an influence on what I was doing. Dry Nottingham sprinkled into cold cider took 2 days to start bubbling and 3 days for krausen. Rehydrated and put into room temp juice I had bubbles in 2 hours and krausen overnight.

 

Foam from aeration or not, I pitch dry yeast right on top and leave it alone. It starts within 12 hours, gets the FG to where I want it, and it tastes good. End of story.

By the way, US-05 rocks.

 

I rehydrate. In my experience, and in my research, everything points to better results from hydrating the yeast.

 

Even if it makes no real difference, I rehydrate so I can see the yeast proof. It makes me feel better knowing they are alive before pitching.

 

Cider tends to not have the same yeast nutrients as beer... or at least from my understanding. It is not a surprise to me that a cider took longer to show visible signs anyway... but then the fact that the cider was "cold" would exacerbate the problem.

 

http://www.homebrewtalk.com/f163/rehydrating-vs-not-rehydrating-484728/

For best results, ALWAYS rehydrate dry yeast.