Are the yeast dead?

[cimirie]

Never had the need to use yeast nutrient until yesterday. I made a big DIPA (1.095) yesterday and was using 2 packs of US05. Went to rehydrate the yeast and threw in DPA-based yeast nutrient (5 tsp) in the cup. After 30 minutes, I had no froth or foaming (which I thought odd), but I pitched anyway.

Now this morning I found one source that says too much DPA will kill yeast. Is it fair to assume that that's exactly what I did?

Thanks.

 

[BigB]

It very well could be... that is a massive amount of yeast nutrient. But obviously you want to sit it out a couple days to see. However, I would be tempted to add an additional package of rehydrated yeast to be safe (with no nutrient).

 

[badhabit]

I use 1/4 tsp per packet so 5 tsp would be enough for 20 packets. I don't know if there are different types of nutrient of what yopu recommended add ition would be.

 

[cimirie]

I use 1/4 tsp per packet so 5 tsp would be enough for 20 packets. I don't know if there are different types of nutrient of what yopu recommended add ition would be.

I read a few sources that said one teaspoon per gallon. But my LHBS sells it in "bulk.". ie, no directions.

 

[BigB]

For a high gravity wort, you could get away with that much. But the way I read your post is that you put it in a "cup"; presumably the rehydration vessel. The ppm of yeast nutrient would probably be hundreds of times greater than appropriate. Plus, yeast are fragile at the rehydration stage... their cell walls are very permeable. Most lab guys only recommend the use of sterile, warm water for rehydration. After the cells have rehydrated, they can better regulate what enters their walls. Therefore, you should have added the yeast nutrient to the wort, rather than the hydration vessel.

 

[beerkrump]

Yowza! I feel sorry for those yeast. They wake up from a long sleep looking for a glass of water and end up getting omelets shoved down their throats.

I'd throw a pack of S-05 in there as soon as you get a chance.

 

[aguajamaica]

Never had the need to use yeast nutrient until yesterday. I made a big DIPA (1.095) yesterday and was using 2 packs of US05. Went to rehydrate the yeast and threw in DPA-based yeast nutrient (5 tsp) in the cup. After 30 minutes, I had no froth or foaming (which I thought odd), but I pitched anyway.

Now this morning I found one source that says too much DPA will kill yeast. Is it fair to assume that that's exactly what I did?

Thanks.

Well, yeah. That probably what happened.

 

[badhabit]

For a high gravity wort, you could get away with that much. But the way I read your post is that you put it in a "cup"; presumably the rehydration vessel. The ppm of yeast nutrient would probably be hundreds of times greater than appropriate. Plus, yeast are fragile at the rehydration stage... their cell walls are very permeable. Most lab guys only recommend the use of sterile, warm water for rehydration. After the cells have rehydrated, they can better regulate what enters their walls. Therefore, you should have added the yeast nutrient to the wort, rather than the hydration vessel.

If you did put it in a cup of whatever water/wort along with the yeast to hydrate, I would try again. The cost of a couple packets of dry yeast vs an entire batch.....
I buy my nutrient bulk as well so don't know brands or brand differences as far as how much to use