"Estery smell/flavor in many of my runs

[CuriosityKilt]

Hello,
I've followed this forum for a few years but first time posting. I've been learning distillation techniques for a few years, made many mistakes, learned from them and kept on going. This site has been a big help/inspiration so thanks for that. I now feel like I have a pretty good handle on things and have a few recipes I can make with consistent results. Which is what leads to my question...

Whether I do a rum, whiskey or a neutral wash my distillate has this prevalent smell/flavor combination that I can only describe as estery. If you have ever done a mead and had that green yeasty flavor that can be so hard to clean up, it is reminiscent of that but not quite the same. Although if you took that mead and distilled it, you might get what I'm talking about. It isn't a horrible flavor but I don't enjoy it and the worst part is it lingers. It is not at all similar to purchased vodka.

I have a 2" x 36" column with an added sight glass and water cooling. Stainless with copper scrubbies. I can control my power input and easily reach 90% coming out the end. I do not use a parrot (well I use to until I learned better). The odd flavor is more prevalent towards the heads but often runs into the hearts. For all I know its in the tails but is overwhelmed by the other flavors. I don't think it is my equipment, as I know a guy who runs a craft distillery with much larger equipment and his vodka has the same flavor.

I ended up with several gallons of tails and failed runs that I re-distilled into something more pure. Still had the odd flavor. So then I experimented with charcoal filtering. That took the estery flavor away but gave it an odd oily/sweet flavor. (I used activated charcoal from coconut shells). So my thought was, I'll re-distill it to get rid of that flavor and have a true neutral! And this is where the story gets odd. The estery flavor came back! Now I had done a rum run prior and maybe I didn't clean up the column but I can't imagine what was left would taint 3 gallons?

A few other data points: Oaking cleans the flavor up, as does macerating for gin. Whether they just mask it or chemically change it I don't know. So I guess the question is: What is this flavor and how do you clean it up? Am I missing something obvious? I'm a tad surprised I don't hear more about it, especially since the one other distiller I know has similar results (although he tends to like it).

Thanks for any help!
-Ck.

[still_stirrin]

“Estery” flavor and smell? Like a fruit? An orange? Apples? Pineapples? Grapefruit or possibly grapes?

And this developed early in the distillation run and advanced into the hearts? This sounds like congeners produced in the ferment. It could result from the amount and types of nutrients you’re using. And possibly the strain of yeast and how it’s working.

Now, if you’ve produced and distilled ethyl acetate, it can reduce into fruity esters in the presence of acids like you might get in a rum. A lot of complex congeners are produced in a rum ferment and this is why the experienced rum producers age their spirits a long time.

Hope this helps a little to explain some of the possible causes, if this is truly what your senses are telling you.
ss

p.s. - I’ve noticed that your thread has had a lot of “lookers” but no “responders” besides me. I wonder where all the “experts” are hiding, or why?

[Metalking00]

How do you do your cuts?

[Ben]

Can you talk about your ferment a bit? What is the yeast strain, pitch temp, ferment temp, if using a liquid yeast do you have a starter program, if dry what is your pitch rate?

[howie]

a non-expert might suggest.....................
it seems like you should be looking for a common denominator.
BTW you're only getting 90% on a 36" 2" with packing and you have a power controller. are you running too fast?
are your scrubbies 100% copper/SS?
are you using the power controller properly?
is your column insulated?
is your water supply quality ok?
are your fermenters infected?
rig pic?
just throwing some ideas out, some have happened to me

[Salt Must Flow]

I agree with howie. If you are only getting 90% ABV then you either have poor/loose packing, taking product off too fast (not an adequate reflux ratio), running too high of power (destabilizing the column, not getting good separation), getting tails in your cuts or something like this.

I would back off on your power, slow down the takeoff (increasing reflux ratio) and see if your % ABV goes up. Shoot for the highest % ABV first. Later you can test power levels and takeoff rates to determine where your limits are before quality starts to fall. Another tip would be to dilute your low wines WELL below 40% ABV before doing a spirit run with your reflux column. Diluting to 15% is not ridiculous as it will clean up your product in comparison to diluting to 40% and you won't be leaving but approx 1% ABV or less in the boiler regardless how much you dilute it.

I have used copper mesh and stainless scrubbers for the rest of the column and that worked adequately. I've tried ceramic packing and it performed poorly. I then tried properly sized Lava rock and it has proven to be the best packing so far and dang near SPP (Spiral Prismatic Packing) performance.

[Bee]

If another local distillery has the same, maybe it's the water.

[kimbodious]

There’s three things to consider.

Fermentation. Are you shooting for high ABV by using turbo yeast? If so try lower yielding wash recipes.

Distillation. Are you double distilling? That will help for purification. Is the vapour speed too high giving you smearing? Reduce the heating power to the boiler and aim for an output rate of 1 - 1.2 litres per hour.

The packing. Is there enough packing? The column should be full of loosely packed. Are you running deep in to tails? Rinse the packing from top to bottom after each spirit run.

I had what we used to refer to as “still smell” in my early products until I made the changes as above.

[Ridgeback816]

A while back I did a little experiment with water I made a plan cereal sugar wash ran it 3 times finished product was very clean and we to the store bought all kinds of water spring, distilled, high mineral, high ph, even some fancy ass water with extra ions or some shit, to me they all tasted just like water but they did some funky things once I added the spirt I would start there but in any case it sounds like to me you can make some fabulous gin

[NZChris]

I haven't experienced your problem and I don't run my products how you do, so this is just my best guesses based on what you told us.

You shouldn't be distilling rum, whiskey and neutral the same way.

I know some people do run rum and whiskey using reflux stills, But I don't do it and don't recommend it, so I'm double distilling those in a simple pot still.

You don't say what your wash for neutral is.
I don't recommend trying to make neutrals without stripping the wash and removing a foreshot first, plus 90% ABV is too low.

I know that there are a lot of posts and HBS proprietors saying that having copper in the vapor path is enough, but research says otherwise, you should also have copper in the boiler. If running an SS boiler, I put copper scrap in it. http://onlinelibrary.wiley.com/doi/10.1 ... 0450.x/pdf

[bluc]

Is it a sugar wash? I find they seem to have distinct characters compared to all grain. Early they are harsher and have a distinct flavour early on. Time does a lot to clean them up, let them breath a bit. even the neutrals like tpw..

[bilgriss]

Still_Stirrin. Ben and NZChris pretty much mentioning all the things I would recommend at checking. Usually esters, if that's the right description, are a product of fermentation conditions, nutrients, temperature and yeast. Some are desirable, depending upon what product you are targeting, some are not.

If you are looking for a very neutral product, make sure your ferment has enough nutrients for the yeast, but not excessive. Don't target an ABV that is above what yeast can comfortably ferment. Keep your temperatures in the right range for the yeast. Then when you distill, pay attention to your cuts and keep what you find pleasing.

[CuriosityKilt]

Hey everyone, thanks for the great responses. Sorry my follow up has been delayed, I got swamped.

TLDR; Its probably yeast stress.

I will try and respond to the possible points people raised. One clarification: When I said "I can easily hit 90%" I didn't mean that was my max, I mean I can hit that even if running hot and not working too much at refluxing.

Yeast Stress -
I suspect this is the culprit for a few reasons. It was on my mind but for some reason was never my top thing to solve, probably because it will be the hardest to solve.

Water. I'm just using city water for my brews. I should probably be using campden tablets.

ABV - I've probably been trying to go too high, 10-15%. I have noticed that adding sugar to my molasses rum throughout the ferment (versus all upfront) has made a large improvement. Also, the rums are the most noticeable for the off flavor in general.

Yeast - I've tried several strains. Early when doing a bourbon I was using a champagne yeast for its ABV tolerance but I later found that yeast contributes a lot of off flavors. Especially in cider/mead... It is really bad for those. I've bought turbo yeast that was supposed to be for rum. I've used regular bread yeast which several of the rum recipes here call for. I'll start them on some sugar water with some yeast nutrient to get them going and by the next day they're often blowing all the water out of the airlock. If I'm using packets I'll usually throw a single packet in a 5-6 gallon wash, that is almost certainly too low but I'm confident aeration isn't an issue.

Temperature - I never pitch yeast over 90F. I try to get it down to at least 80F but that can be a challenge. I only brew in the winter as my only spot for the fermenter is in the uninsulated garage. It rarely freezes here and the fermenter is near the house wall but likely drops into the high 30's out there at times. I have a heat band and a wool blanket to keep the temperature up. This usually keeps the ferment in the 70-80F range. Often it will hit that without the heat band and just the blanket. Those little critters can put out a fair amount of their own heat.

Running the still -
I do not insulate the column. I will wrap the blanket around the kettle when trying to get up to temp. See "Cold Garage". I keep my copper scrubbies loosely packed. One of my earliest mistakes was the packing was too tight. I then had to put so much heat into the unit to get anything to come out the end I was getting puking. It took me awhile to figure out why and it is why I added the sight glass.

Heating - I have 1 internal unit and 1 kettle band. When I'm bringing up to temp I use both but as it starts to get close I fully cut the band and then use the controller to back off. Early I try and reflux hard with a slow drip drip. Once I'm past the really foul early smells, I'll mark the volume, toss it and allow a little faster run. I then toss the same volume again. Then I start taking pretty tight cuts until like I'm more into the hearts where I increase the volume of the cuts. Through all of this I'm adjusting heat and/or cooling to keep a fairly constant drip, almost stream. Obviously as the run goes on I have to start putting more in to keep that up.

Pot distilling - I've done a couple whiskey's where I went more pot still mode. The wider flavors definitely cover any off flavors. For the Rums I've been trying to be a bit more targeted on the flavors. But maybe I should experiment with this more. I find, even on my successes, my spirits tend to hit 1 or 2 notes but don't have that full rich body of a lot of store spirits. I've largely chalked that up to aging and proper oaking, etc. There is a lot to explore there that gets us way off topic.

Neutrals - I've done Bird Watchers, Teddy's, potato, and just re-distilling failed products multiple times to clean them up. I can say the 'Vodka' I have now, when I rerun it there is basically no heads. It is pretty much the same product from start till the tails start to pick up funk. But that off flavor persists.

Well, that was a novel but I appreciated the input and wanted to acknowledge all the great input. I have an oat whiskey (from a recipe here) fermenting now that I'll pot distill. Then maybe I'll do one last rum run where I work really hard on controlling yeast stress and see much that turns the dials.

FWIW this is my column but I added the sight glass - https://brewhaus.com/essential-extracto ... i-keg-kit/

[NZChris]

Using Campden is a mistake when distilling. It's hard to get rid of.

[CuriosityKilt]

Even for a pre-boil before the mash to clean up chloramine? I'm not suggesting using it in the ferment. Honestly I've had 0 issues with infections so that isn't a big concern for me.

[MereCashmere]

If another local distillery has the same, maybe it's the water.

Wow holy crap that’s a brilliant thought! An easy fix too to try different water and at least rule it out. Before you do though I’d clean the crap out of my system just to get a fresh run with store bought water.

[MereCashmere]

I have a sneaking suspicion your “estery” flavor might just be the flavor of heads contaminating your finished product. Especially if your “pot still” runs are described as “covering up” the flavors you’re disliking, as the cuts will be a bit more smeared through the whole run.

Try this for one run;

If you’re “equalizing” your column, stop. try doing a slower heat up, get rid of the keg band, and take off a much wider heads cut and tails cut, and a much narrower hearts cut. Don’t do any blending of late heads or early tails. Try and just take the most pure hearts.

Next, let it sit for a day. When you’re ready to proof, get your distilled water the same temp as the hearts. Then, dilute s l o w l y to your desired proof. Let that sit a week, opening every day to burp, then taste it.

I know it’s a lot of work, but after you do this, if it works to get rid of that “flavor” you can start eliminating one of these steps.

For example, proof down immediately after your run instead of slowly the next day. Or, taste it right after proofing. So on and so forth. Good luck and keep us updated.

[howie]

I've just got a benchtop water filter so i can use the tap water in the workshop for brewing.
now i don't have to tote water up & down steps from the filtered kitchen taps.
it's a cheapish way of eliminating chemical town water without major plumbing.

[Ben]

No campden, it will inhibit the fermentation startup. It's used in wine to give the vintner a "clean slate" for their yeast of choice, rather than letting the wild yeast dominate. It will create sulfur dioxide, which you don't want in the still.

If you have chlorine in your water (usually responsible for a wet cardboard flavor, and/or chloraseptic sensation in the beer) you can simply fill your hot liquor tank (HLT) or boiler with water the day before and let it air out, or pre-boil the water for 10-20 minutes to get rid of it. If you are sanitizing with chlorine: don't, its more of a hassle than a benefit. Scrub with plain water then use a no-rinse sanitizer like star-san.

Try switching to a yeast that can easily handle a temp you can provide. Sounds like mid 60's is pretty sustainable for you, look at an ale yeast (us-05 and S04 are both easy). If your controller probe is outside the fermenter set it for 3-5° lower than your target temp. You can raise your temp at the end of fermentation (around the end of day 3), that will ensure fermentation can complete to dry and most of your flavor production happens during those first 3 days of active fermentation. Having temp control is a huge advantage, you should be able to make some great quality products.

Keep your ABV down to around 8%, most beer/wine strains are happy here. When you start to climb above that you get lots of yeast health problems. Their are yeasts and procedures that will get you higher but for something you are going to distill anyway the juice just ain't worth the squeeze.

Taste your beer before you distill it. See if you can find that off flavor, that will help you divide the problem in half (brewery or distillation)

[CuriosityKilt]

The problem is many cities are switching to Chloramine and that can't be removed as easily as Chlorine: https://www.commercialfiltrationsupply. ... ewing.html -- Some brewing sites recommend Campden tablets but sounds like I should stay away from them. I had my eyes on a reverse osmosis filter but those have discharge water that complicates the system a bit.

I'll look more into the system Howie suggested, thanks!

The beer taste is a good idea, I'll try it with my current ferment. Rum's are hard because that molasses has a really strong flavor.

[Salt Must Flow]

A Reverse Osmosis Unit should be able to remove most everything from city water. RO units typically product 2 parts per million of total dissolved solids in water. A decent 75 gal per day RO unit costs $98 free shipping. For $25 extra you can double the output to 150 gal per day. I used to use RO units when I used to live in a city and still use them living on well water.

[Ben]

Brewing water test from ward labs will give you the info you need. That will let you develop a strategy to deal with whatever is going on, or decide you need to bring in water/purify. Could be the water is fine and there is something else going on.

[CuriosityKilt]

Update time! Thanks again to all that provided input.

I did a simple molasses brew but only used distilled or spring water. No Chlorine/Florine in this water!
Safale us 05 yeast was used instead of standard bakers or some of these "Rum turbo yeasts" I've used before.
Temperature was a challenge as we had crazy weather swings. It varied from 60F-80F and was a game of me plugging in the heating band at night and trying to remember to unplug it in the mornings. I should just invest in an Inkbird controller. I hadn't done a rum recently, so no dunder but for this experiment that is probably good. One less variable.

The ferment itself was unusual. Normally my rum runs run hard, blowing all the water out of the airlock. This one was a slow bubble ever few seconds the entire run. In fact, after 2 weeks I had to do the run due to schedule. Final ABV was probably 7-9%.

During the run, I was pretty certain that estery flavor was not there, based on smell alone. I got it up to temp and ran it VERY slow early on, allowing for as much separation as possible. I let the jars sit, loosely covered for 24 hours and just did the tasting.

After being aggressive on tossing heads...
First jar is very clean with a noticeable spice.
Second jar had a noticeable smokey/leather taste appear.
3rd jar was overpowering smoke/leather - into tails jar.
4th jar was significant ABV drop, the typical tails wet cardboard but also pretty sweet. I suspect this was because the ferment wasn't complete.

I mixed the 1st and 2nd jars and added a touch of the 4th for the sweetness. I'm going to let it age on some French Oak briefly to round it out.

Overall I consider it a success!
The major changes in this run in my suspected order of importance:
1) Water.
2) Lower ABV
3) Yeast.

I put Yeast at #3 because I've tried different yeasts previously and it didn't make much of a difference. At least for the rums, it makes a HUGE difference on ciders.

Unfortunately we're now entering the warmer season where it is harder for me to control for (hot) temps. Also, I'm much busier in the summers. But I'll carry these lessons learned into next fall!

[Duffbrew]

Just wanted to toss in my 2 cents, as a long-time homebrewer I have found the estery flavors and smells come from the fermentation stage. Some yeasts will do it if stressed or have to work out of the temp range they were breed for. (Think Steam Beer) Also what are you fermenting in? If it is a plastic bucket/barrel, it may have some scratches in it that are harboring a wild yeast.

I found this on a brewing site, and it may help you

Esters are a fruity flavor produced during fermentation that can vary in taste and aroma between pears, roses, bananas or other light fruits. In very high concentration it can create a solvent-like flavor.
Esters are formed in beer by the “esterification” of ethanol which is the primary alcohol in beer. Ethanol combines with fatty acids and a molecule called acetyl coenzyme (ACOA) forming ethyl acetate. Ethyl acetate’s flavor varies from a light pear-like character to solvent-like in high concentrations.

[The Baker]

I believe distilled water is not the best water for fermentation.
I don't think it has oxygen in it; and oxygen is needed in the initial stage of fermentation.
Of course you could introduce oxygen by long and vigorous agitation...

Geoff

[CuriosityKilt]

"Esters are a fruity flavor produced during fermentation that can vary in taste and aroma between pears, roses, bananas or other light fruits. In very high concentration it can create a solvent-like flavor."

I'd say that is a pretty accurate description. At first it isn't bad because it has a hint of fruit but then it turns solvent-like and lingers...

I am fermenting in plastic Big Mouth Bubbler. I always wash with soap and water and then Starsan, so I don't think its infection. Temp range is definitely an issue but given it was an issue on this last run which turned out well, probably not the major issue. I can dial this in from the heating side with a controller. Cooling will remain an issue until I can build an enclosed unit with an old fridge.


"I believe distilled water is not the best water for fermentation."
Part of the reason I combined distilled water and spring water. I assume some of those dissolved minerals in the water are actually good for micro-nutrients. I don't think O2 levels are typically an issue. I always transfer from my brew vessel to the fermenter using a bazooka screen. This acts a lot like the aerator on a sink. Also, O2 is needed early in the ferment when the yeast are multiplying. I've rarely had issues with that.

I think I'm going to try a Birdwatchers as my last run of the season and control mostly for water and see what the result is. If I can't detect the ester in something that neutral I think we'll have it nailed down.

[zapata]

1. You do know that esters are a 100% natural part of normal yeast metabolism, right? And the overwhelming majority of esters will be ethyl acetate because acetic acid is a normal by product of ethanol metabolism. So somewhere in the 95-99% of all esters will be ethyl acetate. Which smells like different fruits depending on concentration and who is smelling, and a little like airplane glue or other solvents at high concentrations. It's not a problem, you'll never make a wash without it, and you just cut it out in heads as you see fit.

2. That being said, other things smell solventy on their own, and if they are in a mix with other esters you might be smelling multiple faults with multiple causes.

4. Your rum wash would have also 100% made ethyl acetate. It should also be blatantly obvious in the heads of any reflux run. But you didn't notice it? What did the heads smell like? We know all ferments have ethyl acetate as the majority of the esters, all reflux distillers should be able to identify and capture it at will. Can you?

5. Smoke isn't all that normal in a white rum. Where did that come from?

[Ben]

Don't worry about the lack of oxygen in distilled water, it's a non-issue. The act of pouring the water into your heating vessel is enough to get it oxygenated. Beer brewers run hour+ boils, which drives out all oxygen. Little splash into the fermenter gives enough for a healthy yeast breeding cycle.