National Homebrew Club Ireland

 

Planning a brew later this week.   

I have read that rehydrating dried yeast can give better results.    I have never done this before. 

How does this make it better?   

Will it be just fine pitching at 20 degrees. Or should I go cooler? 

The theory behind rehydrating is that it's better to do it in water than in your wort as the sugars in the wort inhibit the amount of water the yeast cells can draw in.

Pitching at 20 degrees is fine.

Just follow instructions in the packet different manufacturers recommend different procedures.

Cheers.  Found this online. 

Fairly straightforward.

http://www.fermentis.com/wp-content/uploads/2012/02/SFA_US05.pdf

I used to rehydrate US-05 but I haven't bothered for a while. It doesn't make a detectable difference. My numbers are still hit all the same and I detect no difference in flavour.

Quote from: Motorbikeman on February 16, 2016, 06:16:12 PM
How does this make it better?   

Faster start, which means quicker pH drop, alcohol production etc. Less chance of nasties creeping in.
But the main reason is that it's good for general yeast health, resulting in a cleaner ferment and better flavour.

Sprinkling on the foam has same effect and isn't that what that producer recommends?

No, not according to this:
http://www.fermentis.com/wp-content/uploads/2012/02/SFA_US05.pdf

From my own experience, the rehydrated dried yeast does take off quicker, so that's why I keep doing it.

Most of the brewing boffins (Jamil et al) recommend also recommend rehydrating dried yeast, as pitching directly into wort reduces its viability.

What's on the back of the packet?

My rule of thumb is, if the packet says 'Sprinkle contents directly onto wort', and the batch is 19L or less, I do what it says.
If, I'm pushing the batch to 22-23L and the yeast is close to sell by date I'd then consider rehydrating.

-Barry

Quote from: CH on February 17, 2016, 01:17:39 PM
What's on the back of the packet?

I dunno. It surely doesn't contradict what's on their website, does it??  ???

Doses for pro v HB batches
Can somebody post a pic?

I'm pretty sure Notty packets instruct brewers to sprinkle, but the pro brewers (buying in large volumes) are instructed to always rehydrate. Always thought this was weird.

Thought Fermentis were different, but open to correction if someone can post a piccie.

http://www.danstaryeast.com/about/frequently-asked-questions

http://www.brewwithfermentis.com/tips-tricks/yeast-rehydration/

Liquid yeast doesn't come with a lot of active cells, so a starter is needed to build them up. Dried yeast comes with a lot of potential active cells, so to get the best out of it you may need to rehydrate. Dry yeast doesn't like sugar solution in which to do this, so if you were to drop the dry yeast straight in the fermenter you could lose some 40% of potential cells. By rehydrating in water before hand, you lose only a fraction of that. To rehydrate, cool 10 times the yeast weight of pre-boiled water to about 30 degrees, and add the yeast (all sterile and loosely covered of course). Don't pour in to your fv unless within 5 degrees of the wort.

Can post a pic later, but I used us-05 on Sunday night. Instructions on pack said sprinkle onto wort.

The instructions say pitch into wort, their website I linked to above says rehydrate.....

Thanks for posting the pic, MM.

A handy way for getting the correct water rehydration temperature is to add 75% cold (20C sterile/bottled/RO) water and 25% boiled water.
That will give you about 40C water, iirc you want to rehydrate the yeast in 35-41C water and then let it cool to pitching temps.

the website says rehydrate or sprinkle and wait. they probably just can't fit all that on a packet.

QuoteSprinkle the yeast in minimum 10 times its weight of sterile water or wort at 27°C ± 3°C (80°F ± 6°F). Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.
Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). 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, then mix the
wort using aeration or by wort addition.

Notty packets say to rehydrate in 100ml water at 30C - 35C, sit for 15 mins, stir, sit for 5 mins, pitch.

I must admit I always rehydrate dried yeast, after I sprinkled it into wort and had it stick at 1020. Probably nothing to do with it but that's the only time I've ever had a stuck brew. I boil the water and then sit it in a bowl of cold water until I get it to the right temperature. After rehydrating I make sure that it is at the same temperature as the wort before I pitch it.

i don't think there'll be much difference either way, unless the packet of yeast is already on its last legs. :)

Quote from: ManseMasher on February 18, 2016, 12:00:17 PM
The instructions say pitch into wort, their website I linked to above says rehydrate.....

TY I knew I wasn't losing my shit :)

Quote from: CH on February 18, 2016, 08:58:33 PM

Quote from: ManseMasher on February 18, 2016, 12:00:17 PM
The instructions say pitch into wort, their website I linked to above says rehydrate.....

TY I knew I wasn't losing my shit :)

Nicely put dude..