Due to the style of beers I brew, the majority of the time I find myself using SafAle US-05 and S-04. I’ve always had good success but recently read the usage instructions on the Fermentis website and wondered if I wasn’t getting full efficiency.
The instructions state: “Ideally, the yeast will be added during the first part of the filling of the vessel; in which case hydration can be done at wort temperature higher than fermentation temperature, the fermenter being then filled with wort at lower temperature to bring the entire wort temperature at fermentation temperature”.
So, my first question is, are they suggesting making a “yeast sandwich” with the wort; filling your fermentor partially, adding yeast and then filling with the remaining wort? Also, how does one get two different wort temps with the bottom part of the sandwich being a higher temp than the top?
Lastly, if I’m just going to pitch the yeast on top of my full fermentor, do I leave it alone, mix it in with the wort immediately or wait 15-30 minutes like I’m making a starter and then mix it in?
At the homebrew scale I’d argue that everyone is “equipped with a system designed for the rehydration step” since that means a measuring cup and a microwave.
But it’s unnecessary effort. Ask the companies themselves. I’ve heard directly from biologists at both Fermentis and Lallemand who have told me to just skip it in “normal” situations.
When I forgot to ‘fill, stop, fill’ I’ve done that, too.
One advantage to just pouring it in is when I drain the BK into the FV, I run the stream thru a sieve to catch the larger hop chunks from ending up in the FV. This straining creates foam denying access to the wort surface without a wait. Just pouring it in broke thru the foam right down to the wort.
I believe Denny is right. I brew lagers and simply pitch my dry yeast right on top of the wort after or during the racking to the fermenter, but I pitch at a higher rate (3 sachets for a 10 gallon batch, minimum and 2 sachets for 5 gallons, typically). For what it’s worth, I used to rehydrate, but I simply found no significant difference. This is my anecdotal finding - no science behind it, so for what that is worth.
I chucked in my S-04 about a quarter of the way up the fermenter today. No reason other than I like to enjoy that yeasty, bready aroma before the racking is done. Comforting, that.
Signs of fermentation started in about 4-5 hours.