How much yeast is too much?

[Muss]

I rehydrated a dry packet of Safale K-97 in a mug of water at about 25 Degrees Celcius for 15 mins, then added a heaped teaspoon of malted wheat. After 30 mins it showed no activity but I pitched it in the brew anyway.
After 30 Hours there was absolutely no activity. The water in the airlock had not moved at all and the brew was clear.
I purchased another pack of K-97 from the same brew store and rehydrated that at 27 Degrees Celcius for 15 mins then fed it dextrose a couple of times over an hour, maintaining 27 Degrees. Even after an hour there was very little activity on the surface but I still pitched it in the brew.
20 Hours later theer is a very small layer of foam on the top of the brew and the water in the airlock has moved a little, but no bubbles yet.
I suspect that most of the yeast in both of those packets were dead and I'm considering getting some more K-97 from a different shop and pitching that in.
This is a Wheat beer and the fermenter has been steady on 21 Degrees Celcius the whole time.

My question is: Will pitching too much yeast in have any negative effects and how much yeast is too much?

 

[joshpooh]

As far as I know the only negative effects of overpitching is a possible blowoff. If there is foam on top of the brew however, that is a sign of fermentation. I would wait and see if the second batch of yeast you pitched does its job before pitching another. If you see small bubbles now, the yeast should reproduce enough to see larger bubbles or airlock activity by tommorrow.

 

[Muss]

Cheers.

Will the live yeast cells actually multiply to the required amount?

 

[joshpooh]

I think it will. If there is enough in there for you to see visible signs of fermentation (the foam on the brew). There should be enough to reproduce to the required amount. hopefully someone else will chime in, but I'm pretty sure my information is accurate here just from my experience. I only worry when the wort looks the same as when it went in the fermentor. If I see some sign of fermentation it always comes out ok.

 

[RichBrewer]

Everything I've read says to rehydrate dried yeast in warm water only. I don't think that should have made a huge difference but it might have had an effect.

 

[Kayos]

Cheers.

Will the live yeast cells actually multiply to the required amount?

Yea...that's what they do. Start with some and multiply a billions times or 2.

 

[Glibbidy]

You'll be fine, as a homebrewer it is virtually impossible for you to overpitch. You should be concerned more about underpitching then overpitching.

 

[Muss]

Awesome. It's been a few hours since last inspection and the foam is looking a bit thicker Hopefully by tomorrow it will be violently fermenting away.

 

[jayflap]

The best resource that I have found about yeast count is Jamil Z's page, http://www.mrmalty.com

Great resource about yeast!!!

It is very difficult to overpitch as a homebrewer, but in my opinion we typically underpitch as hombrewers. Again, it is my opinion, but just dumping in a smackpack or vial is underpitching and your beer can be made better with a higher pitch rate.

J

 

[casebrew]

How good is your thermoneter? Did you boil the life out of your yeasties?

With dry yeast, I usually make a semi-starter . Once I get my mash water going, I add the yeast to a cup erso of warm water that I have sweetened with anydamnsweetstuff- table sugar, malt extract, dextrose, whatever is in the cupboard. By the time I need to pitch it, it is making foam. So I know it is good yeast, and RDWHAHB instead of fretting for the next day or so.

 

[Muss]

It's a decent thermometer from the brew shop and not one of the floating ones.
The brew was fermenting violently yesterday with 1 bubble every 2 seconds. It's slowed down to a few bubbles a minute now so I'm a happy chappy!

I tasted a commercial Duuvel, Hoegaarden Grand Cru and a Chimay last night. Foah they were really nice and I'm having a hard time choosing which one to clone next! I heard the Chimay beers have the original yeast in the bottles, so it can be cloned really well