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High Attenuation

Jenileo

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Hoping I can get some pointers on some new issues I am coming across in my beer.

Since moving to the new location which is in a different state I have run into various issues that seem to be associated with the water. I have since started to brew with RO water and most of the issues have gone away but one that is left is high attenuation in all of my beers regardless of mash ph, mash temp, yeast and fermentation temp. Recipes that previously finished with attenuation in and around mid 70% are now finishing at mid to upper 80% which is causing my beers to taste dry, thin and for highly hopped beers, the bitter is sharp and harsh.

It seems that the common denominator is the water, but I'm surprised to see it in the RO beers as well. I use a mix of Beersmith and Bru?n water to build my water profiles and I check PH throughout my entire process. My starting mash PH among those beers has been in the range of 5.2 - 5.45 taken approx 10-15 minutes into the mash.

I typically mash 152-155 for 60-75 min depending on the beer and these have all dried out. I have used Wyeast 1056 and London Ale III both new yeasts and I did a starter. I also have used Safale 05 that I sprinkled in over the wort. Among these beers I have used 5 different fermentation vessels one being brand new.  All of these beers are attenuating 83-88%.

Would love to hear some thoughts on what this could be.

Thanks!
Jen
 
The first thing that comes to mind is a wild yeast or other contamination.  Assuming that these are all-grain with no simple sugars added, it is really hard for US-05 or 1056 to reach that level of attenuation and WY1318 would certainly not get up there.

While water chemistry does have some bearing on the effectiveness of the enzymes, it would not make that much of a difference, especially if you are in the same pH range as you were in your last location.

Which does bring up another question (sorry for the stream of consciousness here), is there a big elevation difference between your former location and present one?

 
Oginme said:
The first thing that comes to mind is a wild yeast or other contamination.  Assuming that these are all-grain with no simple sugars added, it is really hard for US-05 or 1056 to reach that level of attenuation and WY1318 would certainly not get up there.

While water chemistry does have some bearing on the effectiveness of the enzymes, it would not make that much of a difference, especially if you are in the same pH range as you were in your last location.

Which does bring up another question (sorry for the stream of consciousness here), is there a big elevation difference between your former location and present one?

I hate to burst your bubble but I've had us-05 hit 90% many times so what you stated is not accurate. And I wouldn't say he's got a wild infection it's possible but highly unlikely
 
Hey guys,

I?m not discounting the contamination, perhaps a wild yeast I just don?t know where it would come from. My cleaning and sanitation methods are pretty aggressive. I thoroughly rinse the plate chiller with a hose hooked up to my mop sink and attached to the chiller. I turn up full blast on hot and I run it through all directions until I get all the hops/grains out. I then put it in a bucket of hot PBW then let it soak at least overnight. I clean my pump by running hot water through it then circulate hot PBW and allow the PBW to sit in the pump overnight. For good measure I plan to run boiling water through my chiller again since it?s been a few brews.

In total I have brewed 10 beers since August, all of them have over attenuated. I have 5 vessels to work with and I even bought a brand new one and had the same results.

Oginme has a a good question on altitude. Yes we did change altitudes. I was in Denver CO before, now I am in MO. This was actually brought up today when I talked to my local brewery about my issue. He mentioned that perhaps I am oxygenating too much at this new altitude. I?m not sure if that would show this significant of a difference in the attenuation from what I was getting in CO, but a good point and another lead to look into. He suggested instead of pushing pure oxygen, to just try doing the old shake method and seeing if that makes any difference.

Any thoughts on the oxygen theory?

 
Ck27 said:
I hate to burst your bubble but I've had us-05 hit 90% many times so what you stated is not accurate. And I wouldn't say he's got a wild infection it's possible but highly unlikely

I would highly recommend the following books:

Biochemistry of Beer Fermentation by Eduardo Pires & Tomas Branyik

and

Yeast by Zainasheff and White

 
In terms of possible contamination, it is hard to test unless you have done a forced fermentation test on that particular wort and your attenuation is higher than the forced fermentation result.  If you have some of the yeast cake from that fermentation, you can do a culture and check for possible other species growing aside from yeasts.  If it is a wild yeast, it would be a bit difficult to distinguish but some common contaminants such as pediococcus can be distinguished by the culture and cell size pretty easily in a cell plate.

The Oxygen theory is interesting.  From what I remember, the presence of too much O2 leads to a lack of expression of yeast character.  With all that oxygen, the yeasts would produce more sterols, stronger cell walls and thus more efficient reproduction.  This over production of yeasts takes away acetyl-CoA used for the Krebs cycle thus slowing down ester formation and other flavor by-products.  Thus, more yeast cells usually results in that loss of yeast character.  This would suppress ester production from the WY1318 and produce a cleaner product, but not necessarily increase the attenuation from the yeast. 

It may also result in a higher level of fusel alcohols due to the lack of acetyl-CoA and incomplete breakdown of the sugars as the yeasts use the oxidation of the fusel alcohols to create more NADH to support their metabolic cycle. 

Everything in my library states that yeast attenuation is highly linked to the wort fermentability.   
 
Hmm.  Interesting problem.  What was the fermentation temperature? What method do you use to control it? 

Contaminants usually develop slowly and have minimal impact on primary fermentation.  Certainly possible...but the controls seem to minmise the likelihood... Including the brand new fermentor. 

What time frame are we talking about for final OG?

What method do you use to measure gravity? Hydro or refrac?

Have you cross checked your mash temp measurement method? 

What mashing method do you use? Old skool cooler or direct control (rims etc). 

 
Greetings Jenileo - I believe the altitude and atmospheric pressure are playing a roll in your dilemma.  Have you thought about simply mashing at a slightly warmer temperature? Say 8-10 degrees warmer than what you normally mash at?
 
I was kind of thinking the same thing as KellerBrauer, but so far have not come up with anything that would explain much higher attenuation.  The pressure difference would account for an increase in yeast activity (extrapolated from studies of yeast growth and attenuation under hydraulic pressure of fermenting tanks) equivalent to several degrees higher in fermenting temperature over what you had been experiencing in CO.  What literature I do have does not indicate a significant increase in attenuation over the normal range that the yeast strain will present in a forced fermentation testing.  A forced fermentation test on a standard wort is typically what the yeast companies will state as the high end of the attenuation range that they claim for the yeast. 

Still scratching my head on anything else that may present that type of difference in apparent attenuation.
 
Thanks everyone! It is a head scratcher for sure! I have a beer fermenting currently that I mashed on the higher end of the range i was working with before, 156. I also omitted the salt additions since the RO water is also a new variable I'm working with. I think that was a good start. Now that I know about the oxygen,  I am going to come up with a strategy for the upcoming beers based on what I have learned here and other forums/brewers and start making beers changing one variable at a time. Hopefully, it is the oxygen and it will just be a matter of a 2-3 batches before I pinpoint the issue. Thanks again everyone, if you have any other thoughts please let me know. I will be sure to update this thread with my findings as i think this is an interesting and possibly rare problem.

Cheers!

Jen
 
Have you checked the accuracy of your thermometer(s). If you're relying on a dial thermometer, it's very possible that it was jarred around during the move and knocked out of calibration.

I use a dial thermometer only for monitoring strike and sparge water until they get close to temperature. I then use a reliable digital for precision. A couple of brews ago the strike water just looked hotter than the dial thermometer read, so I checked with both the digital and a spirit thermometer that I know to be accurate. The dial was reading almost 30 degrees low. Not sure what happened, but glad I found the problem before doughing in.

 
When I run into problems like this, I like to double check all of my measurement equipment, and then start proving that I CAN manipulate the problem by going extreme on one variable and then the next. 

Eg mash at 162 or something "crazy".  Don't do any oxygen.  Don't make a starter, etc. 

One thought might be to do everything at once trying to get the lowest attenuation possible.  Then starting walking variables back in to see what drives the attenuation.

The rationale for going full on extreme is to proved that its not something totally weird. If you do everything and it's still 90pct you know to start thinking much farther afield outside the typical things. 

The steps after that would be to make a plain extract batch in a sterile container with a single yeast vial straight from the store. 
 
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