After aerating theres alot of foam on top in the carboy. If i use a couple drops of fermcap, and then pitch dry yeast on top will it effect the yeast?
No, it shouldn’t. When adding to fermenter, the recommendation for Fermcap-S is 2 drops per gallon, from my recollection. Personally, I always add it to the boil to prevent boil-overs (3 drops per gallon) which also takes care of fermentation.
+1, That’s how I use it too Toby, when I use it. My larger BK has allowed me to limit my use since last fall
I already added (just 3 drops of 5 Star Defoamer 10) to my boil, which worked fine, but now when i aerated in the carboy its foaming back up. I would think that if it stays on top of the wort in the BK it would NOT transfer to the fermenter since i never draw that far down.
It doesn’t stay on top of the wort. It ‘mixes’ into it. Foam is basically bubbles forming groups and merging and expanding. Anti-foaming agents just help to keep them from binding together.
I would recommend taking the little extra time to properly re-hydrate your dry yeast and then pour the slurry in, the foam won’t be an issue then:)
I have the 5-star.
You have to add it to the fermenter when the krausen is up not before. As with the boil it only works and prevents once the foam has started rise.
I’m assuming Fermcap works the same way.
Testing has shown no advantage to rehydrating in terms of performance. Yes, you may end up with more viable cells, but it doesn’t appear to matter to the quality of the beer.
I’ve read the same but IME I’ve achieved better results rehydrating and it eliminates the problem the OP questioned at the same time:)
Then obviously you should keep doing what you’re doing! I’ve found absolutely no difference in the quality of the finished beer.
Question for the folks who don’t rehydrate: Are you still using one package or do you use two? (Let’s say for something around SG of 1.055 or so.)
I’ve fermented US-05 without rehydrating with good results, but I’ve always bumped up to two packages. Haven’t tried it with only 1.
One pack unrehydrated up to about 1.070
Nice, that will save a few bucks.
Do you aerate the wort when pitching US-05?
Yes, yeast require O2 through the growth phase
Sometimes yes, sometimes no. Doesn’t seem to matter.
MY understanding is that one doesn’t need to account for “growth rate” with dry yeast because there are already enough cells in the pitch. In an average beer.
That being said, if I remember/have time- the wort get aerated before the pitch anyway. Not much of a difference IMO.
Yup, that’s why I was wondering if it made a difference between 1 pack and 2 packs when not rehydrating and not aerating.
Actually, dry yeast needs nowhere near as much dissolved O2 as liquid yeast. The reason being is that dry yeast is propagated aerobically in a bioreactor. Propagation in bioreactor allows the glucose content in the medium to be held in a steady state below the Crabtree threshold of 0.3% glucose weigh by volume. The result is that all growth is via the respirative metabolic pathway. Propagation via the respirative metabolic pathway results in yeast cells with fully charged ergosterol and unsaturated fatty acid (UFA) reserves (it is also over an order of magnitude more efficient).
All reproduction in batch-based liquid yeast propagation and beer fermentation is fermentative because the glucose level is above the Crabtree threshold. What yeast cells do when O2 is available is shunt it along with a small amount of carbon (sugar is carbon bound to water) to the respirative metabolic pathway for the production of ergosterol and UFAs.
With a batch propagated liquid culture, initial O2 demands are based the point in the process where the cells are harvested. Pitching a culture when it reaches high krausen places a lower O2 load on the wort because the cells still have ergosterol and UFA reserves. Waiting until a culture reaches quiescence (i.e., waiting until it ferments out), increases initial O2 requirements because the mother cells that were alive while O2 was still in solution share their ergosterol and UFA reserves with all of their daughter cells. Allowing culture to proceed beyond high krausen results unnecessary ergosterol and UFA depletion. Reproduction after the end of the exponential phase is for replacement only.
Thanks for the explanation, so in my process I rehydrate my dry yeast and aerate the wort with an aquarium pump for about 15 minutes while the CFC fills the primary. Are you saying that the aeration prior to pitching the rehydrated yeast is not necessary and counter productive?
Aeration when pitching dry yeast is not as critical as when pitching a liquid culture. Whether or not it is detrimental depends on if the culture scrubs the O2 from the wort, which it more than likely does during the exponential phase. What are your apparent attenuation levels?