how should you properly re-pitch dry yeast?

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indybrew79

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I'm in the process of making a pale wheat recipe from Brewers Best extract kit. Did a partial boil, cooled, pitched dry yeast, and went into primary. Fermentation didnt begin until about 30hrs and has been slow. Decided to repitch but was curious whether it is ok just to sprinkle dry yeast on top of partially fermented wort or whether i need to stir it in?
 
I would rehydrate according to package instructions and pitch when rehydrated.
 
First, fermentation as the sticky at the top of the beginner's forum states, can take up to 72 hours to even begin. So there's no need to repitch if you had fermentation start at 30 hours. That's really good.

Secondly how are you judging how active fermentation is? By the airlock? If so, your rate of airlock has NO correlation as to whether you have a good fermentation or not. An airlock is NOT A FERMENTATION GAUGE, it is only a vent, a valve to prevent EXCESS CO2 from building up and blowing the lid off the fermenter, it is nothing more. You can't judge rate of fermentation, or even if you have fermentation based on what an airlock does.

in fact, there really IS NO SUCH THING as a good or bad fermentation, there is ONLY FERMENTATION. If you have fermentation, then you don't need to add any more yeast.

New brewers have a tendency to feel they need to hover over their fermenters, and "fix" things, even when nothing needs to be done.

There is absolutely NO REASON to waste a packet of yeast. You have fermentation...that's all that matters.

At this point, I bet all you REALLY need to do is,

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To pitch dry yeast do this.....rehydrate. Take a sanitized measuring cup fill to the 1/3 cup mark or so. Stick it in the microwave for 3 minutes or so until its boiling. As it is doing this sanitize two aluminum foil squares , scissors, a fork, the yeast packet, and a thermometer in starsan or equivalent. Remove measuring cup of water insert thermo and tightly wrap with foil square removed from starsan. Place measuring cup in an ice bath, only allowing water to come up 2/3 of the way up the cup or so. The ice bath can cool the water pretty quick so keep checking the temp without removing the foil. You want the water to be between 95 and 105 degrees, so I shoot for the middle at 100. Then remove foil and place upside down, remove thermo, cut yeast pack with scissors and sprinkle yeast on top of the water and replace foil. Wait 15 to 20 minutes. After this time, stir in the yeast with the sanitized fork, it will clump on the fork, so it does take some time, I sometimes scrape off the clump on the sides of the cup and continue to stir until mixed. I try to do this fast because the yeast is exposed at this point. Recover with the second foil square. Wait another 15 minutes or so. Tightly hold the foil to the top of cup and shake gently, not vigorously, or else you will make a mess. Now you are ready to pitch. I try to start this towards the end of the boil, but everything is busy with late hop additions, etc. I have a plate chiller so I can cool a batch quickly= usually under 15 minutes. I use a mix stir stick on a drill to aerate. With this method, I can have fermentation activity in as little as 4 to 5 hours.
 
If ithe beer is already fermenting, then the yeast have multiplied several times, and the beer has a lot more yeast in it than what you have in that packet. Adding a little more won't make any difference.
 
If ithe beer is already fermenting, then the yeast have multiplied several times, and the beer has a lot more yeast in it than what you have in that packet. Adding a little more won't make any difference.

There is a thing as adding too much yeast....


Again, if he has fermentatation, why do you think more yeast is needed?
 
+1 to both of revvy's posts
It sounds like perhaps you didn't areate well, but don't areate now! (Just a suggestion for next time)

Shaking the fermented for 40 seconds is all you need according to WYeast.
 
+1 to both of revvy's posts
It sounds like perhaps you didn't areate well, but don't areate now! (Just a suggestion for next time)

Shaking the fermented for 40 seconds is all you need according to WYeast.

It more sounds like he thinks the rate of his airlock has some correlation to amount of fermentation. In his mind the airlock was bubbling too slow so therefore in his mind, he had a bad ferementation. But we know that that is not the case, the rate of bumbling tells us nothing, it's not like 10 bubbles a minute = 5 gravity points or anything....That's why he really doesn't need to DO anything.
 
Agreed. Nothing to do but wait on this batch. The aeration idea was just a tip that I proposed on a hunch. I think we call all agree that proper areation makes better beer in just about all cases.
 
I think we call all agree that proper areation makes better beer in just about all cases.

From Danstar:

I always aerate my wort when using liquid yeast. Do I need to aerate the wort before pitching dry yeast?

No, there is no need to aerate the wort but it does not harm the yeast either. During its aerobic production, dry yeast accumulates sufficient amounts of unsaturated fatty acids and sterols to produce enough biomass in the first stage of fermentation. The only reason to aerate the wort when using wet yeast is to provide the yeast with oxygen so that it can produce sterols and unsaturated fatty acids which are important parts of the cell membrane and therefore essential for biomass production.

If the slurry from dry yeast fermentation is re-pitched from one batch of beer to another, the wort has to be aerated as with any liquid yeast.
 
Interesting.

I'm surprised that there are enough sterols to support the 10-20x growth that is typical during the cell division phase in making beer. It seems a little dubious because information coming from a dry yeast manufacture as they are trying to sell a product. Call me skeptical, but to me, that reads "Dry yeast is superior, buy our yeast and you'll never need to aerate again!"

Does any one else have information on this? Maybe some experimentation with homebrew?

If dry yeast propagated in an oxygenated environment has enough sterols for cell division in a wort, then would it follow that a starter made on a stir plate would also have enough sterols? Would that mean you don't need to aerate your wort if you use a starter on a stir plate?
 
There is a thing as adding too much yeast....


Again, if he has fermentatation, why do you think more yeast is needed?

I don't think any more yeast is needed. Like I said, it wouldn't even make any difference. I was trying to say I totally agreed with you. Sorry if that was unclear.
 
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