Should I Cool Rehydrated Lager Yeast?

[RobB]

With ale yeasts, I get away with just sprinkling dry yeast on the wort, but I want to rehydrate lager yeasts (s-189 in this case) to ensure that I pitch the maximum number of viable cells.

The manufacturer's instructions say to rehydrate at room temperature, however I was intending to pitch into wort at fermenting temperature (12 degrees). Now I'm worried about shocking the yeast by chilling them so rapidly.

Each solution seems to have a downfall:

Rehydrate warm and pitch into cold wort (as above) - cold shock to yeast.
Rehydrate at colder pitching temperature - against manufacturers instructions, so I'm guessing will result in fewer viable cells.
Rehydrate warm, pitch into room temp wort then chill - I know some people do this, but I'm worried that the yeast will kick off too quickly and it will turn into a race to get them cool before they start acting unlager-like.

Is slowly chilling the rehydrated yeast an option? I think there's a maximum time that yeast will remain happy in plain water.

It seems there is no perfect answer, so what's the least imperfect one?

 

[DU99]

Recommended fermentation temperature: 9C 15C, ideally 12C. cant see you killing it..

 

[felten]

reading from the yeast book it says once the yeast reaches a creamy consistency at the end of the rehydration, slowly and carefully adjust the temperature to within 8c of the wort. You can use the wort from your batch to adjust it by 3c at a time, waiting a few minutes between each addition.