Possible Mash Infection, Need Help

[Tim-o-tee]

Hello All,

I'm the guy with the possible mash infection, and have been reading, researching, experimenting, re-adjusting and upgrading over the last month to try and solve this... to almost no avail...

At first I was thinking wild Brett producing tons of phenols, now I might be thinking an abundance of Lacto because of my significant PH drop during fermentation.  Maybe both? Regardless, I can't seem to do anything to change the outcome of the distillate, which has a strange skunkiness.  It's very prominent in the late heads/early hearts. I can't really describe the taste other than it's quite bitter, and leaves your breath smelling like a Band-Aid.  This flavor comes through in both bourbon mashes and 100% corn mashes.

Sorry for the book but everyone here has provided great info and insight and I'm just hoping to get one more take on this situation.

Ok...

Since this was last discussed I've:

Installed a UV "Air Scrubber" on my HVAC system

Installed a UV light on my RO water system

Installed a cooling system on my fermenters

Installed a CIP system on my mash tun

Cleaned the entire distillery top to bottom

Scrubbed, soaked, rinsed and sanitized every piece of equipment I own

Adjusted my mash protocol to as follows:

Bourbon Mash- about 2.3 lb/gallon

1. Add Silk City's suggested amounts of the various mineral supplements to RO water (Magnesium Sulfate, Sodium Bicarbonate, Calcium Sulfate, Calcium Chloride, and a bit of Calcium Carbonate just because..)

2. Add corn and rye at 125F, let rest for 20 mins (PH at this point is usually around 6)

3. Add high temp amylase and heat to 180-190F for 90 mins (mash stays nice and liquefied)

4. Cool to 150F, add malted 6-row, cellulase and amyloglucosidase, rest for 90 mins

5. Cool to 72-74F, re-hydrate yeast (tried 3 different types of ADY) in room temp spring water (BRIX is usually 19-20)

6. Adjust mash PH to 5-5.2 using citric acid (afraid of using backset until I figure this out)

7. Pump to fermenter, add hydrated yeast slurry, and set cooling to not allow ferm temp to get above 77F

Ferments look and smell great, fairly vigorous.  I have been covering my open fermenters with plexiglass which seems to inhibit the formation of a pellicle. Ferments seem to go for about 3-4 days.  I'm usually ending up with a 2-3 BRIX and a PH of 3.7-3.9. I can only assume that something is causing PH to drop and killing off yeast?   I can smell a slight off odor at this point which is pretty much indescribable, other that just slightly chemical.  I can't compare this smell to anything else I've ever smelled.  It's not overwhelming, just smells like beer with a weird twinge. Kinda plastic-y.  Diminishes slightly when I leave the distillate sit in a stainless barrel for a few days, but returns tremendously when proofing water is added (RO).

I have brand new yeast, grains, AND enzymes.

I've been trying to adjust protocol in order to reduce the chances of wild Brett with lower fermentation PH and temp, but that hasn't helped.  Been trying to keep everything as clean and sanitized as possible to reduce any bacteria but that hasn't helped.  I once cooked all of my grains at 200F for 90 minutes to try to eliminate bacteria from there but that hasn't helped. Everything I've done has resulted in almost 0 change in distillate flavor.  Kinda strange since I'm coming from no ferm temp or PH control, and no minerals added to RO water, and no good mash protocol. 

I clean with PBW, Sodium Percarbonate, and sanitize with Star-San.  Thought of using caustic, but I have open fermenters so i'd have to have caustic sloshing around in there while I scrub, so I just stick with the safe stuff.  I run PBW through my mash tun at 180F for a couple of hours, then rinse with 180F water for an hour.

Can anyone think of any other way I can reduce the chances of wild yeast/bacteria?  Any info is greatly appreciated... and put to use!   Thanks guys.

 

[Foreshot]

Honestly you probably should call a consultant. Dr. Heist at ferm-solutions.net, white labs, or someone else that identify a sample of the infection. It's better than losing product.

[MGL]

Is the fermented mash still looking all infected like in the earlier picture? Or is it gone?  Do you have any gaskets or parts of your still that aint ethanol rated that could give the wines a smell?  Hire a real consultant, looks like it's cheaper than throwing more money at it.

[Southernhighlander]

There are no gaskets or parts of his still that are not ethanol rated.  If there were, there would be 270 more distilleries with the same problem.

[MGL]

1 hour ago, Southernhighlander said:

There are no gaskets or parts of his still that are not ethanol rated.  If there were, there would be 270 more distilleries with the same problem.

Its strange that none of yer customers never ever modify or change parts like gaskets that they might buy elsewhere. A hundred percent retention rate? Get over ytourself.

[Silk City Distillers]

I'm stumped, phone an expert.

A 2.3 pound/gallon ferment that can finish in 3 days seems fairly improbable that other microbes are outcompeting yeast, or could even get a foothold.

The fact that it happened with a fully-boiled mash is fairly surprising.

Unless we are missing something major here, like you are fermenting in a dirty dumpster.

By the way, a sulfur fraction late heads, early hearts, this is fairly common and if it's significant is usually a sign of yeast stress or yeast nutrition issue.

 

[MGL]

have u also tried it without RO water? unless yer tap water is bad theres no reason to do anythign other than filter the chlorine out with carbon.

Just try a simple mash with tap water, grain, enzyme and yeast.  Ferment in yer mash tun or still if you can. That will eliminate all other variables and infection sources.

Ph drop is fine and normal. Yeast create the acid that causes it.

[Roger]

You're overthinking it. Use tap water, and pitch at 85.  If you want to cool it back down after it gets violent, then do so. You are chilling out your yeast while allowing some grain bacteria to eat the sugars. 

[SpiritedConsultant]

I am also surprised that all of your changes have not fixed the problem. Could be that your yeast is simply very stressed. This could be due to low viability at pitching, under-pitching and/or insufficient oxygen at the start of fermentation (yeast need oxygen to produce some essential sterols and to multiply, so DO at the start of fermentation is beneficial).
It is also possible that the problem could originate with your grain. Have you tried doing any batches with grain from a different source? Grain might not be rotten, but could still have residue or contaminants that cause off flavors.

[Thatch]

Since your in NY State, you might want to contact Aaron MacLeod who teaches malting at Hartwick College.  Aaron does grain and malt analysis.  He will likely have to charge you a fee but you'll know for sure if is it your grain.   macleoda@hartwick.edu

[Tim-o-tee]

Hey everyone,

Thanks again for the input, I'll try to answer all of these.

1. My fermented mash looks good, just has a slight plastic-y smell.  I was researching pellicles and it seems like not much is known about the formation of them.  One theory suggested that pellicles form after exposure to oxygen. I would say that is probably true since when I started covering my fermenters the pellicle would not form anymore.  That didn't eliminate the infection just inhibited the pellicle.  But when I allow the pellicle to form then things really get nasty and smelly in there!

2. I am new at this so I wouldn't know what Sulphur would taste like coming out of the still.  It doesn't smell like Sulphur, and I don't have a Sulphur smell in the fermenter (although I have experienced that before).  It doesn't have much of a smell coming off the still, it's more about the taste and then the smell on your breath after sampling.  It's definitely a solvent/Band-Aid smell on your breath.  That's what was making me lean towards excessive phenol production somehow.  From research it seemed to me that a likely source of that would be wild Brett, and I figured PH and temperature control would regulate that.

3. I have tried mashing with tap water only with the same results.  As far as the PH goes, I knew it should drop but from reading things on these forums I thought 3.7 to 3.9 might be too low.  It it ok? I thought maybe the PH drop would kill yeast before they were finished?

4. I would love to not overthink this.  I've pitched at 85 before and the fermenter gets to 95 or above, and from what I've read here it doesn't seem like that's a good thing either.  I'd love to be carefree about all this.  The strange thing is that the distillery that I learned from is as carefree as it gets.  They've never had any infections, they pitch at 80 or above in open fermenters with no temp or PH regulation and they produce thousands of gallons of great whiskey every year.  I once asked the guy "do you check your PH?"  and he basically looked at me like "what's that got to do with anything?".

5. I have tried different grain sources as well.  3 to be exact.  All with similar results.  I've tried different pitching rates and procedures too.  Right now i'm pitching about 2.5g per gallon but have gone as high as 5X that.  I've pitched ADY directly into the mash, and have taken the time to rehydrate, both with the same result.  I don't have a way to test the oxygen content at the moment, but I splash fill my fermenters and it seems to get pretty bubbly from doing that.  Do you think that's good enough?  Is it too much oxygen?  Seems like there might be a fine line but I don't know. I thought I read that Brett likes a lot of oxygen so I don't try to aerate by any method other than that.

I wondering if anyone can tell me what the off-flavors taste like in a Lacto infected batch?  or wild Brett? 

Can you guys tell me what is absolutely critical that you do cleaning wise between every cook and ferment?  (that isn't obvious of course)

I'm still plugging away... Regulating fermentation temps I think has made a slight improvement, but hasn't eliminated it completely.  I'm still afraid to leave the cover off of my fermenters because if that pellicle does come back I'll definitely have to scrap the batch.

Thank you guys for your insights, or at least humoring me... 

 

[RobertS]

Lacto will smell funky similar to pungent sour cream. Brett smells like band-aid, wet horse, old leather, or medicinal depending on strain and concentration.

Everything you describe sounds like infection to me. Is there a dead leg where you may have dirty wash lurking and waiting to pitch an infection into your next batch? Your CIP cycle might be missing a section of your transfer set up.

[Tim-o-tee]

The things I most worry about are my transfer hoses and pump.  I don't have a way to soak these huge hoses so I usually rinse them out then blast star san through them with a sprayer, but obviously I can't tell if I've hit every square inch.  With the pump I have run star san through it, but lately I've been running some sodium percarbonate throught it and rinsing really well.  The distillery I learned from didn't even go that far, they just run hot water through everything between batches.  I was hoping that I could also eliminate this cleaning step but I don't know.  I remove all removable parts and valves from my equipment and soak them in SP then star san. 

I have heard that Lacto may be resistant to Hydrogen Peroxide?  Does anyone else have any knowledge about that?  I was thinking about trying some iodaphor or something like that.  Any suggestions for cleaning agents?

The only other think that I worry about is that there are some tiny weld porosity pinholes at the bottom of my fermenter in the corners...  I usually fill the bottom of the fermenter and add percarbonate and let it soak for a while hoping that if there's anything hiding there then that should take care of it.  Should these pinholes be a huge concern? 

[Southernhighlander]

Tim,

I'm sorry, we must have missed the porosities during our welding inspection.  I had no idea.  I want to send one of my guys to your distillery to take care of that right away.  Give me a call and let me know when would be a good time.

 

Thank you.

[Denver Distiller]

A few pieces of information are missing.  As I wrote before, what you are describing is a lactobacillus infection that is creating acrolein in the ferment and distillate

1. describe the stills you are using.  Made out of what?  Plates?  What's your condenser made out of?

2. When you say you cleaned everything, does that include your still and condenser?

3. How many minutes are you mashing?  In other words, how many minutes from when you first mix water with grain until you're cooled, and have emptied the mash tun?

4. How long does it take you to cool your mash?

5. How many hours is it from when you cool and add yeast until you put it in the still?

6. Describe your milling process, and what does your grist look like?  I'm assuming you don't have sieves.

7. I'm assuming you are double distilling this in two pot stills.  Is that right?

8. What are the exact names and brands of enzymes you are using?

 

My first advice is to drop that high starting gravity.  You said elsewhere on the thread that your ferment stopped at 3 brix.  Likely this is actually >5, correcting for alcohol.  What this means is that you are fermenting 75% of your available sugars, leaving the remaining 25% for the lactobacillus to feed on.  What's worse is that you're wasting 1/4 of the grain you bought.  If I were you, i'd cut my grain bill by 1/3rd, and start there.  Your yeast will make quick work of the sugars, and your hydrometer should read below 0 in 72 hours with no problem.  It should also deny lactobacillus the food it needs, assuming you are mashing correctly.

 

Cheers

 

[Tim-o-tee]

Thanks again for the interest.  Answers to your questions are below:

1. describe the stills you are using.  Made out of what?  Plates?  What's your condenser made out of? We have electrically heated stainless steel baine-marie style pot stills with water in the jacket as heating medium.  Our column is a 4 plate copper whiskey column, non bypassable, and a stainless steel deph and condenser.

2. When you say you cleaned everything, does that include your still and condenser?  Yes, I create a loop from the bottom of the still pot up through the condenser and down through the column with my CIP pump.  I use the pot to heat water to 180 and run PBW through everything, then rinse with 180 degree water.  All of this over several hours.

3. How many minutes are you mashing?  In other words, how many minutes from when you first mix water with grain until you're cooled, and have emptied the mash tun?  From first adding grain to emptying the mash tun is about 7 hours.

4. How long does it take you to cool your mash?  Takes approximately 2 hours to cool from my last rest temp of 150-155 down to 72-74 using a copper immersion chiller.

5. How many hours is it from when you cool and add yeast until you put it in the still?  From pitch to spit is about 92 hours.

6. Describe your milling process, and what does your grist look like?  I'm assuming you don't have sieves.  I purchase milled grain from a large commercial mill that isn't dedicated to the brewing/distilling industry but does serve that market.  Our corn is like fine cornmeal, almost flour but not quite.  Our rye is definitely flour, it's like moon dust.  Malt is just a rough grind.

7. I'm assuming you are double distilling this in two pot stills.  Is that right?  No this is single run in one still.

8. What are the exact names and brands of enzymes you are using?  Bio-Cat Thermostable Amylase HTL, Bio-Cat Cellulase 2XL, Bio-Cat Amyloglucosidase 400L

[Bier Distillery]

2 hours ago, Tim-o-tee said:

7. I'm assuming you are double distilling this in two pot stills.  Is that right?  No this is single run in one still.

Have you tried double distilling and/or running slower?  I have a feeling you're just smearing heads, hearts, and tails.

[Denver Distiller]

3 hours ago, Tim-o-tee said:

Thanks again for the interest.  Answers to your questions are below:

1. describe the stills you are using.  Made out of what?  Plates?  What's your condenser made out of? We have electrically heated stainless steel baine-marie style pot stills with water in the jacket as heating medium.  Our column is a 4 plate copper whiskey column, non bypassable, and a stainless steel deph and condenser.

2. When you say you cleaned everything, does that include your still and condenser?  Yes, I create a loop from the bottom of the still pot up through the condenser and down through the column with my CIP pump.  I use the pot to heat water to 180 and run PBW through everything, then rinse with 180 degree water.  All of this over several hours.

3. How many minutes are you mashing?  In other words, how many minutes from when you first mix water with grain until you're cooled, and have emptied the mash tun?  From first adding grain to emptying the mash tun is about 7 hours.

Ok, that's a red flag.  7 hours is a long time in a mash tun.  And it occurred to me:  what are you using to heat up your mash?

You're moving right through temperature that lactobacillus likes at a very slow speed without yeast competing for food and nutrients. This is giving the lactobacillus a head start.

 

It's really difficult to diagnose this from a computer without seeing and tasting your setup.  It could be anything from improperly rinsing out your condenser and leaving chemical in the thing, leading to an off flavor......to what I mentioned before:  acrolein (which could be described as band aid/phenolic) from lactobacillus.  Acrolein can stick to the inside of your still, ruining batches until all internal surfaces come into contact with the cleaning chemical, and are then rinsed.

My advice, for multiple reasons:  try cutting your grain bill by 1/3rd.  To me, this sounds like the most likely culprit.  This will greatly thin the mash, accelerating both heating and cooling, as well as facilitating a quicker fermentation as the yeast has far less sugar to eat, leaving nothing for the lactobacillus.  Target a 12 Plato mash.  Do you know how to do that?   Fight to get in and out of the mash tun as quickly as possible.  And then after 72 hours, get that mash into the still.

If the problem goes away, then you know that the issue is your mashing protocol.  It's also easier to get a far higher lactobacillus count in milled grain.  You're basically exposing all that starch and things like lignocellulose to the bacteria, and then putting it in a warm sack...whereas whole grains have an endosperm protecting it from harm until moments before mashing.

 

[Silk City Distillers]

You are hitting a point at which it's becoming nearly impossible to diagnose, and you've spent too much money and time to continue speculation.  Find a lab, send samples, get it ID'ed.  Let us know.

Or...  if you are a glutton for punishment.

And if you want a really crazy suggestion.  Pitch a specific strain of lactobacillus known to reduce 4-VP/4-VG (Phenolics) and extend your fermentation time slightly to allow the new lacto to do it's job.  Fight your "bad" bacteria with "good" bacteria in hopes of establishing it as a resident bacteria in your distillery.  It's the 4-Vinyl derivatives that are creating the band-aid flavor - BUT - we don't know why they are being created in large volumes.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC92463/

The most intriguing observation was that the concentrations of decarboxylated hydroxycinnamic acids were consistently lower in mixed bacterial-yeast fermentations than in pure-yeast fermentations (Fig. (Fig.6).6). The only explanation for this result is an interaction between bacteria and yeast. Perhaps the rapid substrate decarboxylation effected by the bacteria results in the 4-vinyl derivatives accumulating at an early stage, followed by reduction to the 4-ethyl derivatives by the yeast. If decarboxylation by the yeast is rate limiting in this process, mixed cultures will provide rapid transformation into the ethyl forms. Alternatively, one of the major differences between a pure-yeast fermentation and a mixed fermentation with lactic acid bacteria is a greater reduction in pH due to lactic acid production by the bacteria (2, 14). It is possible that the reduction of 4-VP occurs more favorably under these conditions.

 

[Silk City Distillers]

What yeast strain by the way?

[Tim-o-tee]

This is getting heavy!  Bierling: I have tried running slower actually.  I've drug a run out about twice as long as normal but that didn't change anything.  Maybe even made it worse.   Denver Distiller's info does make sense, although the distillery I learned from uses the same type of grains that I do and also very often leave their mash overnight before final cooling and fermenting with no problems at all. Silk City- I am definitely a glutton for punishment, but I am growing increasingly more Lacto intolerant lately.  Not sure I want to complicate things any more that they already are.  I will try a thinner mash with a lower brix/plato and I believe I can speed up the cooling process a little.  I cook mash in a similar vessel to my still which electrically heats water inside a jacket so I just have to rig up a way to drain the hot water from the jacket without making a huge mess.  Affordable Distillery Equipment is going to help assess my equipment and make sure there's nothing there to encourage bacterial growth.  Before my next run I will perform another comprehensive cleaning and see how that goes. To answer the question about yeast strain, I have mainly just been using generic DADY yeast, but have also tried a couple other commercial AD bread yeasts with the same results.  I don't even know if Red Star DADY has a POF+ or - rating, does it?  I was hoping to work my way towards White Labs once I get to a point where I can get to taste the full actual flavor profile of my distillate using different strains.  If the next run doesn't improve I will definitely be looking for a lab.  Can anyone suggest a lab that deals with this situation?

[MGL]

Hire. A. Consultant.

[Patio29Dadio]

I am late to the conversation here, but reading the mash protocol my first guess was that the fermentation start needs more O2.    Starting out with an anaerobic mash, please the issue with the RO water, it sounds like the yeast are not doing their aerobic party before they have to get to work.  That mash protocol includes a lot of cooking and resting which would deplete O2. 

I have a wand with a HEPA filter and a high quality aeration stone connected to an O2 tank and bubble the mash for a few minutes right after it goes into the fermenter and before pitching.    From my perspective getting the yeast colony up to strength before going anaerobic does a lot to kill off the foreign organism risk. 

[Goodtimes]

I second the motion to increase your 02 concentration.  It's an easy way to insure your yeast are happy and healthy, and an 02 setup is a cheap overall investment.

[Denver Distiller]

Adding more oxygen will increase the lag phase (the time it takes for the yeast to consume oxygen, create daughter cells, and finally begin fermentation)...the opposite of what he wants to do here.  Essentially he'd be adding several hours more for any bacteria to multiply without actively fermenting yeast competing for food. 

He's using dry yeast.  He just needs to activate the yeast properly, and pitch at the proper rate to consume all the available sugars.

This isn't brewing, where you're working with a freshly boiled substrate that has a low plate count.  What is in his fermenter is loaded with healthy lactobacillus from his malt....if the yeast isn't fermenting, that means the lactobacillus is......

Just trying to help, and just my opinion....