Primary/ airlock

[Norwayson]

Hello all, I've begun primary fermenting on a chocolate stout that I'm pretty excited about. This is my second beer and I had a question about my yeast activating/ fermentation beginning. After topping off my mix to five gallons, I pitch the yeast on top and aerate. I had the same results both times I have brewed,as there would be absolutely no movement of my airlock at first, but six-eight hours later, it's going at it. Is this okay? My local brew shop guy said incubating wasn't necessary and I could just pour the yeast on there. Are there any possible negative effects?

 

[dyqik]

That's normal. Full yeast activity won't start for 8-24 hours after pitching, even with a proper sized starter and good aeration. And airlock activity is not a reliable measure of yeast activity (the CO2 may escape via some other route if the lid isn't well sealed).

 

[DRonco]

Sounds like good practice to me. I generally aerate before I pitch. Other then that, sounds right. I almost never hydrate dry yeast. Instead of mixing the yeast in 80° water, I just chill my wort to 75/80° and pitch. Same thing to me and I don't have to worry about keeping another bowl sanitized.

 

[Norwayson]

Thanks for the replys. Thats a brow of sweat I can wipe off.

 

[peterj]

Sounds like good practice to me. I generally aerate before I pitch. Other then that, sounds right. I almost never hydrate dry yeast. Instead of mixing the yeast in 80° water, I just chill my wort to 75/80° and pitch. Same thing to me and I don't have to worry about keeping another bowl sanitized.

You should rehydrate yeast in 95-100F tap water, not 80F. Rehydrating in water (not wort) is important because when the dry yeast cells are first rehydrating, they can't regulate what goes in and out of their cell walls. Putting them straight in sugary wort damages the yeast cells and has been seen to kill up to half of them, which could result in underpitching. It usually works out ok in normal gravity beers, but it's best to rehydrate in water.

Also pitching into hot wort can cause off flavors if it isn't cooled down very quickly. The best practice is to pitch the yeast at the temperature you want to ferment at.

 

[Komocabo]

Isn't 95-100° WAY too hot? Wouldn't that kill the yeast too? I thought proper pitching temps (even when hydrating) is critical. That temp seems to go against standard temps... What am I missing?

 

[DRonco]

You should rehydrate yeast in 95-100F tap water, not 80F. Rehydrating in water (not wort) is important because when the dry yeast cells are first rehydrating, they can't regulate what goes in and out of their cell walls. Putting them straight in sugary wort damages the yeast cells and has been seen to kill up to half of them, which could result in underpitching. It usually works out ok in normal gravity beers, but it's best to rehydrate in water.

Also pitching into hot wort can cause off flavors if it isn't cooled down very quickly. The best practice is to pitch the yeast at the temperature you want to ferment at.

I understand the the science of hydrating in water rather than wort, but the directions for a packet of us04, for example, say:

" Sprinkle 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."

 

[peterj]

Isn't 95-100° WAY too hot? Wouldn't that kill the yeast too? I thought proper pitching temps (even when hydrating) is critical. That temp seems to go against standard temps... What am I missing?

I understand the the science of hydrating in water rather than wort, but the directions for a packet of us04, for example, say:

" Sprinkle 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."

95-100F is not too hot at all. Danstar recommends rehydrating between 30-35C (86-95F) on their products. And according to this response from Dr. Clayton Cone of Danstar (http://koehlerbeer.com/2008/06/07/rehydrating-dry-yeast-with-dr-clayton-cone/), it's much better for the yeast to rehydrate them between 95F and 105F. He says it's actually detrimental to rehydrate cooler than that.

I tend to trust advice from Danstar more than Safale. One reason is that on the US-05 packet they don't even tell you to rehydrate at all but in the online data sheet they do. Maybe their products are different and need different temperatures, but I doubt their process of creating the dry yeast is different and obviously yeast do well at the higher temperature. He says the lower you go with rehydrating temperature the more you damage the cells. That combined with pitching directly into wort which can kill up to 50% of cells is a recipe for a huge underpitch.

 

[boydster]

Isn't 95-100° WAY too hot? Wouldn't that kill the yeast too? I thought proper pitching temps (even when hydrating) is critical. That temp seems to go against standard temps... What am I missing?

Rehydrating and pitching are different animals. Yeast will do quite well if pitched into 95° wort and allowed to ferment at that temp, they love it in fact, but they make off-flavors at that temp that can be prevented by fermenting slower (at a lower temperature). For rehydrating, we want the yeast to be in an environment that is ideal from the yeast's vantage point rather than the brewer's, so temperatures of 95° or 100° are better. Since there is no fermentation happening at this point, no off flavors can be produced.

 

[Komocabo]

Sorry... I'm a ****... I use liquid yeast, so that temp made me concerned...

Carry on then!

 

[Norwayson]

Rehydrating and pitching are different animals. Yeast will do quite well if pitched into 95° wort and allowed to ferment at that temp, they love it in fact, but they make off-flavors at that temp that can be prevented by fermenting slower (at a lower temperature). For rehydrating, we want the yeast to be in an environment that is ideal from the yeast's vantage point rather than the brewer's, so temperatures of 95° or 100° are better. Since there is no fermentation happening at this point, no off flavors can be produced.

What type of off flavors would be produced in the case of just pitching yeast, not rehydrating?

 

[boydster]

What type of off flavors would be produced in the case of just pitching yeast, not rehydrating?

If a packet of yeast has 200 billion cells, you end up with about 100 billion viable cells to start with due to cells dying from osmotic shock. For most 5 gallon batches, that is underpitching and the off flavors would be similar to pitching a single tube or smack pack of liquid yeast with no starter.