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Fermentis US-05

Simie

Simie

Brewer
Joined
Dec 28, 2009
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Location
Montague, MI
Hi all. This is kind-of a silly question, but here goes anyway. We made up a batch (11.5 gallons) of a New Albion clone the other day. We do 11.5 so we can pour off sludge when we put it into primary fermentation and after secondary fermentation we leave a little sludge in the bottom of the carboy as well. I suppose we waste a little but we have clearer wort and finished beer by leaving some of the dead material behind. Now to my question. Based on 11.5 gal. we needed 2.3 packets of US-05. I don't want to sound cheap but am just curious; is it okay to fold up the remaining dry yeast, tape it closed and use the remainder of the packet at a later date. Generally, we just dispose of the remainder, but hey, if it's okay then we could use up the remainder. Thanks all and am hoping for some input. And I do realize I'm only throwing away a couple of bucks....Thanks..Simie
 
If you really want to be cheap, save the sludge. Seriously. If you poke around here you'll find plenty of info on washing yeast. Basically, you can turn that sludge from your primary into the yeast for your next couple of batches.  How does 2.3 packets of US-05 (my workhorse by the way) for three or four batches sound?
 
Kernel, No we just added it in dry. I've had good results both ways so it depends on the mood I'm in regarding hydrating.
Maine Homebrewer, I'll look into it. But we may be too long between batches....I'll see. Thanks guys. Simie
 
Jamil says you lose 50% cell count by not rehydrating.  Mr Malty calcs are based on rehydration when using dry yeast.  When you are not rehydrating you should pitch the rest of the pack and then some to get to your correct cell count.  Have you done a comparison brewing the same beer using rehydration vs non?
 
You can fold it up. Some people used to talk about buying it in brick form and just breaking off chunks of what they needed. Store it in the fridge.
 
Kernel, thanks for the information; guess we will be rehydrating from now on. Grathan, sounds good to me. Thanks all..
 
KernelCrush said:
Jamil says you lose 50% cell count by not rehydrating.  Mr Malty calcs are based on rehydration when using dry yeast.  When you are not rehydrating you should pitch the rest of the pack and then some to get to your correct cell count.  Have you done a comparison brewing the same beer using rehydration vs non?
Click to expand...
What's the difference between rehydrating with water and rehydrating with wort (as you pitch dry into it)?
 
Beer_Tigger said:
KernelCrush said:
Jamil says you lose 50% cell count by not rehydrating.  Mr Malty calcs are based on rehydration when using dry yeast.  When you are not rehydrating you should pitch the rest of the pack and then some to get to your correct cell count.  Have you done a comparison brewing the same beer using rehydration vs non?
Click to expand...
What's the difference between rehydrating with water and rehydrating with wort (as you pitch dry into it)?
Click to expand...

Osmotic pressure.  As the yeast begin to absorb water, initially the cell membrane cannot control what flows across the boundary.  Everything flows in and out of the cell upsetting the needed balance of nutrients and salts inside the cells.  This immediately kills roughly 50% of the cells. 

Even with plain water it is still important to rehydrate at the right temperature (95 - 105F).  Too cold or hot will also kill the cells. 

I wouldn't bother saving a partial packet of dry yeast.  If I were that worried about the cost of yeast, I would re-pitch from batch to batch.  Plan you batches back-to-back, so you can repitch healthy from one batch to the next.  Then take a couple months off and drink. 

Once a packet has been opened, the yeast inside is compromised and time is NOT on your side.  They are packaged dry and sterile.  Once you open it, moisture and possible infection gets in.  The viability of the yeast is highly questionable after another month.  Why risk it?  What costs more?  0.7 packets of yeast, or a batch of beer?
 
tom_hampton said:
Beer_Tigger said:
KernelCrush said:
Jamil says you lose 50% cell count by not rehydrating.  Mr Malty calcs are based on rehydration when using dry yeast.  When you are not rehydrating you should pitch the rest of the pack and then some to get to your correct cell count.  Have you done a comparison brewing the same beer using rehydration vs non?
Click to expand...
What's the difference between rehydrating with water and rehydrating with wort (as you pitch dry into it)?
Click to expand...

Osmotic pressure.  As the yeast begin to absorb water, initially the cell membrane cannot control what flows across the boundary.  Everything flows in and out of the cell upsetting the needed balance of nutrients and salts inside the cells.  This immediately kills roughly 50% of the cells. 

Even with plain water it is still important to rehydrate at the right temperature (95 - 105F).  Too cold or hot will also kill the cells. 

I wouldn't bother saving a partial packet of dry yeast.  If I were that worried about the cost of yeast, I would re-pitch from batch to batch.  Plan you batches back-to-back, so you can repitch healthy from one batch to the next.  Then take a couple months off and drink. 

Once a packet has been opened, the yeast inside is compromised and time is NOT on your side.  They are packaged dry and sterile.  Once you open it, moisture and possible infection gets in.  The viability of the yeast is highly questionable after another month.  Why risk it?  What costs more?  0.7 packets of yeast, or a batch of beer?
Click to expand...

Next time I buy a package I'll have to rehydrate with the correct temperature and do a cell count.  I did a cell count on a packet of US-05 recently and even after re-hydrating the viability was 25%.  The total cell count in one package was about 80 billion cells.  So the osmotic pressure was out of the cell instead of into it as it would be with wort.  The water was at room temperature instead of 80 degrees as per the data sheet.
 
Woodland, thanks for your informative and articulate response. From now on....I will rehydrate and then pitch what's not used. Thank you all for your time and insight. Simie
 
Whichever dry yeast you use, check for the MFRs recommended temps for rehydrating that yeast strain.  They do differ by MFR.

The Safales seem to be 80F +/- 6F, or 74F to 86F, while the Danstar Nottingham is higher, at 86F to 95F. 

Saflagers' temp is lower than ales, at 74F.    The MFR sites have PDFs you can download and keep handy. 
 
Have had great results with GoFerm.  Its a nutrient powder you dissolve in your hydration water while your waiting for it to cool down....the time to add it is at 110F....before you add the yeast to the hydration water.
 
Freshness of the hop pack (and how it was stored) can have a great difference in # live cells, just like in liquid.

I've had packs that just arrived at the homebrew shop start a ferment on an IIPA in a couple of hours. Conversely, I had a pack a year old (although stored at 35 degrees F) take 18 hours to get started in a Pale Ale.

Another good reason not to buy yeast in bulk!
 
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