Silk City Distillers

Ok, lots of work to do here.

That is not "Kahm" yeast, it's a fairly typical pellicle.  It would be impossible to identify the specific microbes from the pellicle alone, but given the mash protocol, there are a good number of potential candidates.  Achieving that kind of pellicle in 5 days, or 1-2 days after the cap drops, is fairly impressive, that's a substantial bacterial load.  Congratulations.

Here goes.

1. You can not mash with RO water, unless you add necessary minerals back to the water.  This is the source of the yeast stress I mentioned.  Yeast will not be able to effectively reproduce in a wash made with only RO water, as it's missing a number of crucial minerals.  I suspect this fermentation is taking a long time, in addition to stalling, due to the yeast ultimately dying out and failing to reproduce effectively.  In addition, the lack of calcium ions are going to significantly reduce the efficacy of the enzymes.  Need to fix the source water.  As a test, you can try using 50% RO and 50% tap water to reduce whatever the offending issue is, until a better water treatment solution can be found (carbon treatment, nano/ultrafiltration) or adding back minerals (building water from scratch can be very costly in the long-run).

2. Related to the RO issue.  If he is hydrating the active dry yeast with RO water, he is likely killing a good amount of yeast cells in the process due to the osmotic shock before even pitching.  Alone this wouldn't be a massive problem, but in conjunction with #1 it's making it worse.

3. The mash protocol sucks (sorry, it does), I'm not sure who trained him on that approach, or if he developed it himself, but it's suboptimal.  We don't know the total grist used to hit 19 brix.  If it's around 500lbs (per 265g batch), it might be ok.  I'm not going to dwell here except to say that the way the mash is being done, it will create lots of unfermentable dextrins, which are loved by non-yeast bacteria as food (like brett), and will likely result in what looks like a stuck fermentation.

4. Everything above tells me that bacteria are out-competing the yeast here.  The yeast and the bacteria are standing on the starting line of a race, and before the race starts, someone goes up to the yeast and beats the hell out of him with a baseball bat.  The starter then proceeds to throw tacks all over the lane the yeast is running in, wishes the bacteria good luck, and then starts the race.

5. Proof of this is the fact that adding 1g per gallon of Fermaid K improves the situation.  While I wouldn't call this overdose, in an all grain mash this amount should be entirely unnecessary.  So adding the Fermaid K is fixing some of the issues caused by the RO water.  It's adding back some of the missing minerals, it's also giving a slight boost to the yeast.  We're talking about 2 pounds per 1000 gallon mash here, that's quite a bit.  Given the fermentation stalling, and limited yeast reproduction, I'm going to hold my ground here and say that at distillation time, we have an abundance of nitrogen left in the wash that is causing a problem.  Once the RO issue is corrected, he can likely dial back the Fermaid K additions substantially.  I would suggest continuing to use it, at about 1/4 the current dose rate, as "insurance" until the mash and fermentation protocol is dialed in well.

6. Don't ferment at 90 degrees.  The poor yeast.  This is causing major yeast stress.  This is going to result in a massive amount of heads, and combined with the already high stress environment, create a very sulfury wash.  You don't make good whiskey at 90f.  Until he can resolve the other issues, I would recommend keeping the fermentation in the low 80s.

7. Drop the pH at the time of pitching to closer to 5.2 using acid.  The increased acidity will help the yeast outcompete the bacteria.  5.8 is a very happy place for bacteria.

Once these things are taken care of, I would suspect the "bleeding heads through hearts" issue to go away - this is a direct result of acid production by the bacteria.  Also the skunkiness will be eliminated as well, this is the direct result of yeast stress.  Yield should likely improve substantially, and reduction of the nitrogen will result in reduction of any of the remaining off flavors.

Get the mash protocol straightened out too, it's an inefficient use of grain and enzyme.

Lobe pumps work great for both.  Invest the money up front and enjoy decades of flawless performance.

Keep in mind that aluminum is not compatible with caustic or acids commonly used for CIP.  Either of these at recommended temperatures will end up destroying your pump over time.

When you select your mash/wash pump, you can size it for double duty as your CIP pump.  You'll want to make sure you have a VFD/Speed Control on your pump so you can dial it fast or slow as necessary.  We use our mash pumps as CIP pumps.  Same applies to your hoses, if you buy hoses that can stand up to the CIP temperatures, you only need one set.  Nice thing is, once your CIP is done, your pump is clean, and your hoses are clean.

A Neuroscientist and you aren't working on a more cerebral spirit (har har)?

Lots of focus on terpenes as psychoactives these days, along with other potential (non-proven) "health benefits".  Alpha-pinene or eucalyptus (1,8-cineole)as AChE inhibitors, Limonene as an anti-depressant, Linalool as a sedative, Myrcene as an analgesic.  All fairly common terpenes found in typical gin botanicals.

There seem to be multiple problems here, not just one factor in play.  Sounds like possibly overdosing nutrient, coupled with a stalled fermentation.  Going to result in a lot of residual nitrogen and sugar in the wash, which together are going to create a ton of non-pleasant off-flavors (scorched, smoky, bitter, etc).  These are mostly Maillard reaction products, which require sugars (primarily monosaccharides/glucose, nitrogen/amino acids, and heat to generate, the dead giveaway being the dark color of the stillage.  @Ak2 is dead right here.  Running slower is just going to cause more time under temperature, thus more Maillard reaction products.  Whatever is causing the stalled fermentation, is likely causing significant yeast stress, and thus the sulfur aroma/flavors.  The yield in PG is probably abysmal, this would confirm it.

The open/closed top is a red herring, it's purely coincidental at best.  It stops fermenting when the top is open, because someone opened the top and noticed it stopped fermenting, or stopped fermenting shortly thereafter, or jiggled the tank a bit to release some co2 bubbles, saw it was bubbling, but then it stops.  Schrodinger's Cat Whiskey.

We need to know what the whole protocol is to help any more I think, otherwise just conjecture.

I don't know if anything supersedes TTB Ruling 79-9, but it seems to indicate the TTB recognizes the difference between Entry Proof and Barrel Proof, even though there haven't been changes to the CFR to memorialize it.

The Bureau of Alcohol, Tobacco and Firearms has recently recognized the need to establish guidelines for use of the terms "Original Proof," "Original Barrel Proof," "Entry Proof" and "Barrel Proof" on distilled spirits labels. 

No standard definitions have been issued by the Bureau specifying when and under what conditions distilled spirits labels may bear phrases indicating that the proof of the spirits when originally produced and when bottled is the same. Previously, the Bureau commented on the use of terms such as "Original Proof," "Original Barrel Proof," "Entry Proof" and "Barrel Proof" on a case-by-case basis. 

Although these terms are to defined in the regulations, they have acquired certain meanings when used on distilled spirits labels. 

To preclude any misunderstanding and to effect standardization in the use of these terms, the Bureau is issuing guidelines as follows: 

Held, a distilled spirits label bearing the phrase "Original Proof," "Original Barrel Proof" or "Entry Proof" indicates that the proof of the spirits entered into the barrel and the proof of the bottled spirits are the same. 

Held further, "Barrel Proof" on a distilled spirits label indicates that the bottling proof is not more than two degrees lower than the proof established at the time the spirits were gauged for tax determination.

Typical centrifugal pump, I would imagine something like 3/4-1hp, although you need to look at pump curves or have your supplier help you select a pump.

How are you moving mash/wash around today?

Rule of thumb for CIP with a sprayball 2 to 3 gallons per minute of vessel circumference, leaning closer to 3 than 2.  This is with the assumption that you can supply the necessary pressure to hit these flow rates, and that your spray ball isn't grossly over/undersized.

For a typical 1000 liter tank that is around 5 foot diameter (~15 feet circumference) that's 30-45 gallons per minute required.

1/2" PEX and City Water probably doesn't stand a chance, the pressure washer won't do anything better.  You'll want to rinse the kettle with a hose of any solids that will clog up your spray balls, then fill the kettle with water and caustic/acid, using a suitable pump to recirculate for CIP.  Use your still kettle to heat the cleaning solution to the target temps.

27 CFR 5.40

Would cost me more money, and take more time, to make an oak box than calling up (Insert Barrel Company Here).  Pretty sure my oak box would be leaky as hell too.  Also consider the capital investment in machinery, space, and good quality oak.  Not to mention the opportunity cost of the time and money, because you could be spending your time and money making whiskey, and not building a wood shop.

Realistically, we're talking about $1-2 of cost per finished bottle, maybe a bit more for smaller oak.  An empty glass bottle costs roughly this much, the label and closures will cost roughly this much.  Used cooperage significantly less, and if you recycle your new oak into used oak products (malt whiskey, corn whiskey, brandy, rum), this overhead is further reduced.

Are you really saying that you'd rather spend your money on the glass, label, and closure - and not the whiskey itself?  That $1-2 on a suitable oak container, which is arguably the most important part of the process, is simply too expensive and you are going to cheap out?

This is crazy talk gentlemen.  The first rule of craft whiskey is to not sell shitty whiskey.  Make all the shitty whiskey you want, but please god don't try to sell it.

You won't be able to strain the yeast out with a strainer bag, your beer will be fairly milky.  You'll see when you squeeze out the grain, it runs like milk.

I reiterate, the flavor contribution of on-grain has more to do with the inclusion of yeast than the bulk grain solids remaining in the wash.  The inclusion of bulk grain has more to do with total yield and batch efficiency, than it does flavor.   Yes, there is some cross-over back and forth, the grain does contribute to flavor, just not as substantially as the yeast.

If you separate the grain post-fermentation, and allow the yeast to fall out of suspension to the bottom, and then distill the remaining clarified liquid, you'll get a significantly lighter flavored whiskey, similar to the style folks are getting when they distill "finished" out of date beer from a brewer.

I've found that even just a few grams of NaOH dissolved in water can move a 500g batch a few tenths upwards.  I'm using granules, and not liquid, as It's relatively easy to find FCC/USP or Food Grade granules (aka prills or micro beads).  We're talking about relatively minor tweaking here, no?

Adjusting your starting pH at the onset of a batch - say if you are using a high backset percentage and have water a bit on the acidic side (or not acidic, but very little buffering capability), again should require a relatively minor addition.  Otherwise consider backing off the backset percentages a bit, or attempting to increase alkalinity/hardness.

I understand this being an issue when barrels were scarce and hard to source because nobody had additional capacity, and it was nearly impossible to get a call back from a barrel manufacturer.  You can pretty much get barrels from anyone in a week time.  Not following why this is still a problem to be solved?

With 5.5kw, I imagine you are running something around 15 gallons size.

You can filter your wash through a paint strainer bag from home depot.  Let your wash settle a day, pour off the bulk, then pour the rest through the strainer bag and give it a good squeeze.  You'll lose some yield, increase your ferment size by 5-10 gallons so you still yield a full still run.

A good portion of the on-grain flavor is coming from distilling the wash with the yeast.

Yes, you are losing yield, but at that scale it's inconsequential, just ferment more to make up for it.

I’d ask for that interpretation in writing, the phone call sounds even more ambiguous than the regulation.  To me, interpreting the situation, “touching oak” means going in a barrel.

Sodium Hydroxide works well.

Keep in mind that Meura, who arguably invented this process, sees mash efficiency of nearly 100%, better than is possible with a traditional Lauter Tun.

From an ROI perspective, mashing larger batches, sepatating pre-ferment, and then ensuring your fermenters and stills are running full of alcohol is going to maximize payback.

The wildcard post-fermentation is yeast biomass, and maybe what is causing your problems.  If you are seeing a mix of dry cake, and wet mush, it means your filter plates are seeing differential pressures.  One section is clogging up, where the other isn’t.

Temp is also a factor, filtering hot works better than filtering cold, it’s a simple function of viscosity. 

If you can crash cool in your mash tun, try filtering a little bit warmer before you move to your fermenters.

Otherwise, you may need to start experimenting with different filter cloth or plate styles.  I am surrprised the manufacturer is no help here. 

You'll be able to find propionibacterium shermanii very easily, it's what cheesemakers use to give swiss cheeses like emmenthaler or jarlsberg it's bubbles.  Any wholesaler of cheese-related cultures can supply it, or likely any hobby cheesemaker supplier.

A little Google-Fu and you'll find something.  For example, here is one in UK, very affordable quantities:

https://cheesemakingshop.co.uk/shop/ingredients/propionic-bacteria/

At a minimum I would suggest co-pitching with a lactobacillus strain, in a non-refined sugar wash that includes a portion of backset.

No.

Are you attempting to filter pre or post fermentation?

Something to keep in mind, just generally, not specifically about the label posted above.

Just because someone managed to get a label through approval doesn't mean it's the label is correct, following regulations, is not misleading, etc.  It also doesn't mean that what a distiller put in the bottle, matches what the label expected to be put in the bottle.  There are plenty of misleading labels that don't follow regulations.

More notable difference in malt whiskey isn't grain in-out, it's yeast in-out.

The other factor to consider - what proof are you planning to bottle at?

If you are planning to bottle at 90, for example, you might lose enough alcohol going in at 92 to put you under your bottling target.

On that note - you guys running a double retort?