Response to Clibit's message. Far be it for me to disagree with a senior member, but my Graham Wheeler book refers to a maximum temperature of 30C for rehydrating yeast . Am I doing it wrong? 5 - 10 degrees difference is a large margin.
I always rehydrate my yeast, and the advantages to me are that it seems to get going quicker and you can tell if the yeast is dud before you hoy it into your wort.
I also whisk my beer before adding yeast, I do worry about how clean a whisk can be though...
Hi James - that temperature range just came from the article linked, which is a decent source, but is that person's opinion. When it comes to pitching dry yeast I believe in doing what works for you cos there are so many opinions around. And I agree about re-hydration letting you know that the yeast is ok prior to pitching. Though a lack of froth doesn't necessarily mean the yeast is dud, in my experience.