Rehydrating Dry Yeast - Conflicting Advice

[mckenry]

Hi All,
I have gone back to good ol' US-05 from liquids for a few APA's.
Its been a while and I had to reaquainte myself with the rehydration process. I found my How to Brew bible by palmer and looked up the appropriate section. I also had a look at Craftbrewers yeast section. Now the two of them give conflicting advice.

One wants me to rehydrate @ 27C the other 37C - both +/- 2-3C

From Craftbrewer;
Re-hydrate the dry yeast into yeast cream in a stirred vessel prior to pitching. Sprinkle the dry yeast in 10 times its own weight of sterile water or wort at 27C 3C.

From Palmer;
Re-hydrating Dry Yeast
1. Put 1 cup of warm (95-105F, 35-40C) boiled water into a sanitized jar and stir in the yeast. Cover with Saran Wrap and wait 15 minutes.

Does this really matter which I use?
I have used Palmers every time in the past. I find with US-05, I get to about 1.018 then it stalls. I rack to secondary and away we go again, down to usually 1.010 - 1.012 - which I am happy with. The beer is fine.
Does the hotter rehydration cause this, or is it more to do with mash temps and other brewing processes?

Interested to hear what others think, especially if you rehydrate @ 27 and how low your FG goes. Typically my O.G is around 1.056.

Regards,
mckenry

 

[Supra-Jim]

I can't offer much in a way of explaination, but i've always rehydrated my dry yeasts at around the 27deg mark. I know Palmer says you can do it at 35-40, but something about that doesn't feel right to me (note I'm not questioning Palmer).

Also I've always had US-05 finish around the 1012-14 (brew dependant).

Cheers SJ

 

[therook]

If in doubt look at what the manufacturer recommends

Rook

 

[staggalee]

I always just pitch it dry, never have any probs. with it.

stagga.

 

[Paul H]

What would the bloke at craftbrewer know about brewing?

Cheers

Paul

 

[staggalee]

What would the bloke at craftbrewer know about brewing?

Cheers

Paul

yeah :lol:
but as a matter of fact, if he uses dry, he pitches it dry.
Used to anyway, spose he still does.

stagga.

 

[gap]

Either temperature should be OK. Would not go any higher though. As long as the water is not to hot to kill the yeast.
Should make no difference to your FG, that would be decided by other issues.

Regards

Graeme

 

[raven19]

Rehydrating from dry is going to take some time in either case to awaken the yeasties before significant growth and action starts to occur.

Personally, I would not be rehydrating at over 30 degrees, as you then need to dump your yeast starter into wort that is cooler. A large difference in temp will lead to yeast shock slowing yeast action again...

I tend to lean towards having a yeast grow initially at a similar temperature as the planned wort fermentation temp - I mainly do ales not lagers though.

In the end, what works for you and tastes good to you is probably the best method!

My 2c fwiw.

 

[mckenry]

If in doubt look at what the manufacturer recommends

Rook

Good call. Did so and it would appear Ross' instructions are word for word from fermentis' website.
Now on, rehydrating at 27C.

Ross 1 - Palmer 0 :lol:

 

[staggalee]

I could be wrong, but I think Fermentis used to also say you can just pitch it in without rehydrating first. Pitch, leave for short period, stir/agitate and away it goes.
One thing I found with the us-05 is it performs even better on a 2nd or 3rd reuse of the trub.
When you think about it, reusing a dry yeast was considerd bad form and a no no only a few years back

stagga.

 

[Bribie G]

I find US-05 to be a great yeast for making fake lagers, makes a brilliant fake Cerveza but I have had attenuation problems with it, it hangs around for up to 2 weeks with a frothy little krausen. As mentioned by the OP when I rack it into another vessel and leave it for a couple of days then put it into cold conditioning the beer turns out fine in the end.

 

[crundle]

:icon_offtopic:

Love the kitten's revenge avatar Bribie, looks just like our ginger cat when he was a kitten, and about as vicious too!

Crundle

 

[matti]

If in doubt look at what the manufacturer recommends

Rook

linky

rehydrate or not= BEER

 

[acoulson]

As everyone has said 37 to 40 is way too high- great if you want to select for coliforms but the yeast won't like it much :wacko:

 

[Kai]

37-40 is considered optimum for yeast rehydration but you're not leaving any margin for error on the temperature -- Too high or a thermometer out of whack and you risk killing the yeast.

27 or so is more for 'playing it safe'... you're less likely to kill the yeast yet still providing a warmer environment to help rehydration.

 

[Pollux]

I just dump it into the bottom of the fermenter and then pour from the NC cube at a height, seal with glad wrap and leave it alone.

No issues thus far. To my mind, rehydrating yeast is simply opening up another potential location for infection.

 

[fraser_john]

A winemaker has told me that rehydration at the higher temp is recommended because it constricts the cell walls of the dry yeast, making it quite possible to pitch such yeast without aeration, such as they do in winemaking where dissolved oxygen is not present in any sort of amounts we usually seek for beer production!

Not that I have tried it, but I think its going to go on my experiment list!

 

[Mantis]

I just dump it into the bottom of the fermenter and then pour from the NC cube at a height, seal with glad wrap and leave it alone.

No issues thus far. To my mind, rehydrating yeast is simply opening up another potential location for infection.

Couldnt agree more

 

[acoulson]

A winemaker has told me that rehydration at the higher temp is recommended because it constricts the cell walls of the dry yeast, making it quite possible to pitch such yeast without aeration, such as they do in winemaking where dissolved oxygen is not present in any sort of amounts we usually seek for beer production!

Not that I have tried it, but I think its going to go on my experiment list!

Make sense, also the solubility probably increases with temperature, but I don't see the value of putting the yeast under that sort of stress.

 

[staggalee]

I just dump it into the bottom of the fermenter and then pour from the NC cube at a height, seal with glad wrap and leave it alone.

No issues thus far. To my mind, rehydrating yeast is simply opening up another potential location for infection.

Agree with you, I`ve done both methods {rehydrate and dry} and apart from knowing the yeast is viable by rehydrating, I can see bugger all difference in the finished beer.
Save yourself the work and pitch dry sez I.

stagga.