Effects of grossly over pitching yeast ?

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HerrBrauer
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Re: Effects of grossly over pitching yeast ?

Postby HerrBrauer » Wed Sep 06, 2017 2:33 pm

Ancient Abbey wrote:For these two trials, skip aeration and eliminate this variable as a source of contamination altogether.


Don't you think skipping the aeration can be dangerous when using sulfites? I mean... if you don't aerate and your sulfite level @ pitching is not negligible, then the fermentation performance can be negatively impacted.
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Ancient Abbey
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Re: Effects of grossly over pitching yeast ?

Postby Ancient Abbey » Wed Sep 06, 2017 2:42 pm

Depends on the concentration and yeast strain. Over 75mg/l and one can experience a 2-4 pt difference between the FFT and batch EVG. In this case, we're trying to solve a problem through the process of elimination.
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Nick_D
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Re: Effects of grossly over pitching yeast ?

Postby Nick_D » Thu Sep 07, 2017 11:34 am

Ancient Abbey wrote:No, that's not too much. I regularly pitch 400-500ml of dense slurry for a 20L batch.


Wow, ok. So what percentage of your collected yeast cake would that be ? up to 100% ? for a 12 P beer ?

Ancient Abbey wrote:None. The one thing I noticed when I switched to the Narzis cold profile was that acetaldehyde and diacetyl were below tasting thresholds, with very rare exceptions.....This suggests to me that you are getting too much growth, and it is growing too fast.


Ancient Abbey wrote:Over-aeration can be a major contributor to acetaldehyde. If using fresh, healthy and highly viable yeast, then as a general rule of thumb you shouldn't have to aerate longer than it take to fill the top of the fermenter with foam.


Over aeration....far out. Hmmm, Imagining that my fermenter was the appropriate size, that would only really be an hour or so, with the aquarium pump running ungoverned. Or less.
The health of my yeast is questionable after my starter making process (stir plate etc). Hence wanting to try not messing with it at all. Dry yeast will achieve this :tu


Ancient Abbey wrote:That said, contamination also explains all of your by-product issues. Do you ever keep the batches long enough to see if they go funky, or do you just dump them right away?
Yeah for sure, I've kept them for eternities at cool and warm spunding temps. Especially my early attempts where I thought just waiting long enough would bring the good stuff. Nothing changed. just unfinished by a few points, and the by products/off flavours. Nothing funky developed.

Ancient Abbey wrote:this might be helpful:

http://onlinelibrary.wiley.com/store/10 ... ac6ba59180

Hmm, unfortunately I'm getting a "403 forbidden" screen... :cry:


Ancient Abbey wrote:Are you sure everything you are using is sanitized? Aeration stones and tubing are often where people mess up their batches. Be sure to use 70% ethanol or boiling water as Star San won't kill Sacc or Brett.


I usually do boiling water, then starsan.... Though only starsan on the airstone and tubing now that I think of it....

Ancient Abbey wrote:I agree with Tech, start with packets of 34/70 and do a split bitch (or two batches). Pitch one with a single packet, pitch the second with 2 packets. Be sure to rehydrate them @100-105F using sterile water and a product call Go-Ferm. It will supersaturate the yeast with nutrients as they rehydrate, and since it lacks DAP it will not reduce viability. For these two trials, skip aeration and eliminate this variable as a source of contamination altogether.

http://www.scottlab.com/product-102.aspx


Sounds like a plan ! Not sure if I'll have the means to run a proper split batch....but I'll at least do it consecutively. Without introducing other variables I hope.

Is this the same stuff ? https://www.ibrew.com.au/products/lalvin-go-ferm I'm in Australia, and am not having any luck finding the exact one you posted there.

I just dumped some rehdrated US05 into my current batch. Can't hurt, and might do a job of cleaning up and finishing? Nothing to lose at this stage.
I have Sauergut going for my W34/70 experiment this Saturday..... Will report back, hopefully with good news !

Thanks again.
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Re: Effects of grossly over pitching yeast ?

Postby Ancient Abbey » Thu Sep 07, 2017 12:40 pm

Nick_D wrote:Is this the same stuff ? https://www.ibrew.com.au/products/lalvin-go-ferm I'm in Australia, and am not having any luck finding the exact one you posted there.


Yeah, they are both rehydration specific nutrients. It should be fine.

Interesting note on their page, that vitamins can be inactivated by sulfites. I need to look into that more.
http://www.lallemandwine.com/north-amer ... /3/goferm/

Nick_D wrote: Wow, ok. So what percentage of your collected yeast cake would that be ? up to 100% ? for a 12 P beer ?

I'm usually trying to get 1/2 of my yeast from new cells off a stir plate and 1/2 from a yeast cake. As long as I end up with a minimum of 1/3 new and 2/3 slurry, then I'm happy.
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Weizenberg
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Re: Effects of grossly over pitching yeast ?

Postby Weizenberg » Thu Sep 07, 2017 2:18 pm

You may be better off aerating the yeast in a conical flask, then pitch that. If your yeast doesn't score high in viability and vitality, then the cold schedules can become tricky. You don't want to over-aerate either. That can have quite detrimental effects. Without a meter, you are flying blind. I use welding O2.
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Re: Effects of grossly over pitching yeast ?

Postby Nick_D » Fri Sep 08, 2017 12:02 pm

Weizenberg wrote:You may be better off aerating the yeast in a conical flask, then pitch that. If your yeast doesn't score high in viability and vitality, then the cold schedules can become tricky. You don't want to over-aerate either. That can have quite detrimental effects. Without a meter, you are flying blind. I use welding O2.


When I make another attempt using liquid yeast (after trouble shooting with dry, non aerated W34/70), I will certainly try this. Or are you suggesting aerating the rehydrated W34/70 in this manner ? I have erlenmeyer flasks of 250, 500, 2000 and 3000 mls. Would I mix yeast slurry with some wort and aerate like that ? how much wort ? Sorry for all the questions.

I suspect I have aerated some batches to death (quite literally). Makes for a cautionary tale for other people if nothing else I suppose....

I have welding O2 as well, with flow meter, but no DO meter. I'm leaving my O2 alone though for now, as over oxygenation is apparently very easy. A DO meter is high on the acquisition list.

Thanks !
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Re: Effects of grossly over pitching yeast ?

Postby Weizenberg » Fri Sep 08, 2017 2:47 pm

I use the original W34/70 from the laboratory in Weihenstephan, but also had great results with the Wyeast equivalent.

Nowadays I propagate on stir plates, then a quick burst of O2 into the flask and then pitch at 5Celsius for a slow rise to 7-8 degrees over the next two days.

I also quite like the W838 from White Labs, but you need to keep sulfites in check. Approx 20-25mgl.

I did write all that up on the blog. There you have the details on cell count etc... If anything is missing, let me know.
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Re: Effects of grossly over pitching yeast ?

Postby Nick_D » Sat Sep 09, 2017 12:42 am

Weizenberg wrote:I use the original W34/70 from the laboratory in Weihenstephan, but also had great results with the Wyeast equivalent.

Nowadays I propagate on stir plates, then a quick burst of O2 into the flask and then pitch at 5Celsius for a slow rise to 7-8 degrees over the next two days.

I also quite like the W838 from White Labs, but you need to keep sulfites in check. Approx 20-25mgl.

I did write all that up on the blog. There you have the details on cell count etc... If anything is missing, let me know.


Ahh yes, the actual W34/70. I know the dry isn't the same stuff at all. But just using it to troubleshoot (please don't judge me :P). I look forward to getting back to liquid yeasts when I've ironed out my problems.

How long do you let it go on the stir plate for before giving O2 and pitching? (how quick is a 'quick burst' ?). Are you pitching the entire flask and not decanting the starter wort ? I feel my issues with starters stem from chilling and decanting the starter.

I will re-visit your blog today. It is a wealth of knowledge. Thank you again.
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Re: Effects of grossly over pitching yeast ?

Postby Nick_D » Sat Sep 09, 2017 12:46 am

Ancient Abbey wrote:Depends on the concentration and yeast strain. Over 75mg/l and one can experience a 2-4 pt difference between the FFT and batch EVG. In this case, we're trying to solve a problem through the process of elimination.


I'm currently doing no sparge batches with 40mg/l . Approx 0.7 g SMB for a 12 liter batch. Sound about right ? (That's assuming 18 liters total water used).
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Re: Effects of grossly over pitching yeast ?

Postby Weizenberg » Sat Sep 09, 2017 5:19 am

Why would I judge what you make? That's your own business. After all, you will be the main person affected! ;)

I prefer liquid yeasts since they are more economical for me. A vial can be kept going for a good year when looked after a bit (ask Abbey -- he's a yeast expert).

I really recommend a low pitch at 5Celsius and a slow rise over 2 days to 7, maybe 8 degrees. If you pitch the right amount, you should never have those problems. However, with dried yeast things can turn tricky because I have no idea as to the quality and the actual viability and vitality.

What you are saying sounds to me a bit like:

  • "I'm getting a lot of speeding tickets but I cannot afford to fix my speedometer"
  • "I keep hearing these knocking sounds from my engine but I cannot afford the correct fuel"
  • "The quality of my fermentation isn't good, but I don't want to use good quality yeast while I'm troubleshooting quality issues"
Financially, you can easily keep a vial going for 5 batches. That's often cheaper than using dried yeast -- and you know that qualitatively it will be better.

The sums we are talking about aren't exactly huge either. If you were to ferment 1500hl batches, then yes, economy is a consideration. But your batches are most likely 0.5-0.2hl. It won't matter much.

I often propagate 1x10^9 cells to 1x12^9, which often takes 3 steps and lasts a good week. I do take good care of my propagation medium, which I make from milled malt, but I do decant it. On brew day, I decant and then fill it with cooled wort from the last runnings and add that to a stir plate. I make 50l of beer, so my flask is about 5l. Just before pitch I oxygenate (I do measure it) to 9 mg/l. I have a medical flowmeter attached, and after a while one quickly gets the knack of how long and strong that burst needs to be. I am sorry, but without DO meter you are flying blind since you cannot test the results. On concentrations higher than 34 mg/l, yeast can get damadged.

I bought a DO meter about 6 years ago for exactly that purpose: improving my fermentation. And improve it did. Once I had the correct O2 content in the wort my final attenuation improved noticeably. It is still going. Extech makes great instruments, and their customer support is excellent.

I still use a DO meter mainly for that purpose, but what I didn't expect was that guys like Techbrau, Abbey and Rabe started to stick it into the mash once I convinced them that they needed one! :lol:

You may also have a lot of rubbish left over from the boil. Whirlpooling inside the boil kettle won't be that effective. I found that using a dedicated whirlpool vessel removes a lot more and quicker. Alternatively you can let your wort stand for a while and crash cool it. Then rack the trub before you pitch.

Considering your problems, the mash is the last place you need to consider. Fermentation should be your main focus by now.
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