Rehydrated with distilled water

[gotbags-10]

Oops grabbed the wrong gallon jug of water to rehydrate my us-05. Did I kill my magical munching microbes? I pitched 8 hours ago to a well aererated batch. Normally I wouldn't panic until about 72 hours but haven't done this before either.

 

[Setesh]

Everything I found on the web says that distilled water is lethal to yeast because of osmotic shock. I would rehydrate another pack and pitch it. You aren't out a lot of money by pitching another pack and and you want a good healthy amount of yeast in there. Better to over pitch than to let whatever other microbes might be in there get a foot hold.

 

[day_trippr]

Agreed. This clip sums up the consensus opinion:

"Rehydration in distilled or deionized water is lethal to the yeast. The cell walls require the presence of some minerals, sodium, calcium, magnesium and or potassium, during rehydration. Tap water at 250 ppm hardness is optimum. Most tap water has enough hardness to do the job."

Cheers!

 

[WoodlandBrew]

Where is that quote from?

Danstar mentions not to use distilled water, although the language is not nearly as emphatic:

Do not use wort, distilled water or reverse osmosis water, as loss of viability will result.

http://www.danstaryeast.com/products/nottingham-ale-beer-yeast

Fermentis doesn't seem to mention it.

The most important factor I have seen in viability is how long the yeast floats, which is the next sentence in the instructions from Danstar:

DO NOT STIR.

I've seen better than 90% viability rehydrating US-05 with distilled water. It would be safer to pitch again, but probably not necessary.

 

[gotbags-10]

We'll have a little krausen this morning so I guess I'll just roll with it
View attachment ImageUploadedByHome Brew1425823814.559217.jpg

 

[day_trippr]

Where is that quote from?[...]

http://www.lalvinyeast.com/importance_rehydration.asp

Cheers!

 

[WoodlandBrew]

Thanks! That is quite a reputable source. I wonder if there is any difference in the process of drying that Fermentis uses that would effect rehydrating with distilled water. Perhaps there are salts with the yeast?

 

[pcollins]

I wouldn't worry and you now have active fermentation so I'm pretty sure you're fine.

FWIW, I work in a small craft brewery as head of brewing and spoke at great length to our Lallemand rep who walked us through rehydration of fresh dry yeast. Rehydrate in distilled water is fine. Boiled/cooled is fine. Stirring is fine after an initial 15 minutes of rehydration. Do NOT oxygenate on initial pitch, not necessary. Following those instructions we do just fine.

Speaking to another senior brewer in the business... Do NOT rehydrate, not necessary. ALWAYS oxygenate.

The saying in the homebrew world of "Ask 10 homebrewers a question, get 15 answers" applies equally in the pro brewer world.

 

[RM-MN]

I wouldn't worry and you now have active fermentation so I'm pretty sure you're fine.

FWIW, I work in a small craft brewery as head of brewing and spoke at great length to our Lallemand rep who walked us through rehydration of fresh dry yeast. Rehydrate in distilled water is fine. Boiled/cooled is fine. Stirring is fine after an initial 15 minutes of rehydration. Do NOT oxygenate on initial pitch, not necessary. Following those instructions we do just fine.

Speaking to another senior brewer in the business... Do NOT rehydrate, not necessary. ALWAYS oxygenate.

The saying in the homebrew world of "Ask 10 homebrewers a question, get 15 answers" applies equally in the pro brewer world.

These two responses do sort of make sense. If you rehydrate you get a much higher survival of the yeast so you end up with the right amount for the pitch and reproduction in the wort isn't necessary. If you don't rehydrate and end up killling half of the yeast cells, then aerate the wort, your surviving yeast will have the oxygen needed to reproduce and you still end up with the right amount of yeast.

Now the question becomes "if I rehydrate and aerate, do I end up with an overpitch?"