Rehydrating Yeast Question

Brewing my second and third batches this weekend. I have 2 packs of yeast in the fridge and apparently need to rehydrate. My first batch I didn't put the yeast in the fridge. I got the extract kit, let it sit for 2 days at room temp, brewed and pitched. I had a crazy fermentation the next day (needed a blow off).

Do I really need to rehydrate? Or can i just take the packs out of the fridge the day/2 days before and let stand at room temp? I keep hearing re hydrating is the best but there is also risk involved (Could kill yeast).

Is re-hydrating different for each yeast or is there a general way to do it? I found the below that's pretty general but will it work for all yeast?

1 - Boil 1 cup of water to sanitize and take the oxygen out
2 - Pour boiled water into sanitized jar and cover with saran wrap till the water is below 100 degrees
3 - Pour yeast and let sit for 15 minutes. Do not swirl or mix
4 - After 15 mins swirl to suspend yeast and let sit for an additional 15 minutes
5 - Pour hydrated yeast into wort

I have Safale us-05 and Windsor Danstar yeast.

Any help is appreciated here! I just dropped about $60 on 2 new extract kits and I dont want to mess this up!

Next time I will buy extra yeast packs...how long are yeast packs good for when you stick them in the fridge?

Also, is it ok to make and aerate my wort, leave it in the fermentator for an hour while i'm re-hydrating or should i rehydrate at the same time the wort is boiling?

Thanks

Pitching instructions: 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 (80F ± 6F). Once the
expected weight of dry yeast is reconstituted into cream by this method (this takes about 15 to
30 minutes), maintain a gentle stirring for another 30 minutes. Then pitch the resultant cream
into the fermentation vessel.
Alternatively, pitch dry yeast directly in the fermentation vessel providing the temperature of
the wort is above 20C (68F). Progressively sprinkle the dry yeast into the wort ensuring the
yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes
and then mix the wort e.g. using aeration.

http://www.danstaryeast.com/sites/default/files/nottingham_datasheet.pdf

The people that make the yeast will let you know what to do.

Re-hydration appears to be successful! Within 4 hours i started to notice bubbles. Seems really quick, might be an intense fermentation. Should probably get the blow-off ready just in case.

The only thing i didn't do is stir for an additional 30 minutes. I did 10 times the yeast weight, boiled and sprinkled yeast. Let sit for 15-20 minutes. Stirred (sanitized spoon) and let sit for another 5 minutes. I made sure it was within 5 degrees of the wort and then dumped it in. Appears to be working fine.

Is it really necessary to stir for 30 minutes? Seems tedious...

unionrdr said:

They're talking a bout using one of those magnetic stir plates.

Click to expand...

? what are those and is it necessary?