Molasses wash pH and stuck fermentations

So, we have had some awesome fermentations and some stuck ones, pH seems to be the issue, and even tried to save a couple with sodium hydroxide, but we had as much in that as we did the molasses, and it tasted like crap after the stripping run... My partner blamed it on the dunder, so we went dunder free and still have the problem....

I think I have narrowed it down to bugs making acid during our settling....

we are at ~5.4pH when 20 gallons of 45% sugar molasses(feed grade) is mixed with 25gal boiling water. 72 hours it is down to 5.2-5.3 when we rack off the sediment the first time and add more boiling water, and it is down to 4.0 when we rack the 2nd time and pitch. If it gets fermenting really fast, it rockets down in gravity, but if it doesn't... it sticks... here is a chart of the last three using our Tilt Hydrometers.

I am going to try to speed up the process, but we can't afford to pay our employee full time yet, so workign out a gant chart and schedule to allow a 12-24 hour settlign instead of a 7 day settling, that or use steam injection to get the wash to 180...

I have a couple of 1.5 liter samples going right now in mason jars, one where I brought the sample to a boil with 500ml molasses and 500ml water, then added the other 500ml of boiling water, and the other just mixed... will monitor pH over the next few days..

Charts are overlayed, they did not happen at same time.... blue line is obviously what we want, orange line was next with higher gravity, we thought high gravity stuck it, so did lower gravity with the green line.. well that did not help... (red line is the temp for the blue fermentation

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Comments

  • You are seeing pH drop to 4.0 during your settling process? Wow. You are clearly not pasteurizing the wash to the extent you think you are. What temperatures are you hitting during the mix, and during the settling?

  • edited February 15

    Piggott in Fermented Beverage Production outlines a process for molasses clarification in a way that minimizes bacterial load.

    image

    Reduce to 45 Brix

    Hold at 70c/160f - I would assume at least 1 hour

    Add Sulfuric Acid, Piggott talks about weight to volume addition, I have to imagine this is going to be around the 4.5pH mark.

    Prior to pitching, the pH is adjusted back upwards with lime water/milk of lime/calcium hydroxide.

    We only ever use the high test stuff, so we aren't finding a need to clarify.

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  • Just curious, are you now a TILT convert and swear by it and absolutely recommend it over others, or are there any shortcomings with it.

  • @grim said: You are seeing pH drop to 4.0 during your settling process? Wow. You are clearly not pasteurizing the wash to the extent you think you are. What temperatures are you hitting during the mix, and during the settling?

    clearly... and clearly not high enough... they vary, 145-170.. tried to have my guy use an electric heating element, but he just scorched the molasses by having it on too hot... some of us don't have a fancy steam boiler, or even room for one... LOL

    reading the excerpt, I am not far away from 45 as my molasses is partially pre-thinned by the vendor to 45% sugar...

    I did a test with steam(my espresso maker and 100grams of molasses), I can take it to 190 with steam adding 24% by weight... time to hook up the steam eductor to a 3-phase unikeggle....

    @richard said: Just curious, are you now a TILT convert and swear by it and absolutely recommend it over others, or are there any shortcomings with it.

    Regarding the Tilt Hydrometers I love them, especially with it communicating to a Pi ZeroW with the TiltPi SD card image.. hoping they drop in price

  • Why not attempt to filter in real-time and avoid the settling time entirely.

    Bag filter? Large cartridge filters? One of those little centrifuges that the waste oil biodiesel guys use?

  • After settling a day, there is 20% sludge by volume... Trying not to bring new costs and time-eaters into the distillery... actually not trying, it just ain't gonna happen... I understand additions of pH modifiers, but if I am spending more in chemicals than I do on molasses for a batch, what am I really making?

    The jar on the right that settled faster was mixed hot... I am monitoring pH of both as an indicator of microbial growth...

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  • and hell, sulphuric acid??? I don't need to lower the pH... I already have great rust remover!

    https://www.youtube.com/watch?v=vq5IUiYMhRM

  • What about aiming for a lower starting gravity and trying to ferment faster? Trade time in the fermenter for more passes through?

    Is this the Lu-west molasses?

  • It is not the SG... the orange and green lines both suck...

    This is the same bulk molasses most distilleries in FL use... pretty sure it is just US Sugar standard stuff they ship out by the railcar... in our case, it is cut with water first to be a bit more pourable and less like gelatin... 45% sugar

    I know I have to heat it to 180 or more to kill the bugs, I am just musing about the issue to gean ideas that don;t break the bank, right now putting 30gal of molasses in a drum and using a steam eductor to heat it while adding about 7.5gal of water seems to be the best issue...

    just putting the info out there for others that may get a stuck fermentation with low pH and save them some effort...

    I pitched one yesterday with only a single 3 day settling that was at 4.6 (down from 5.3 at mix and 5.2 a couple days before)) and it has now dropped from 1.115 to 1.094 in 24 hours, and with it expected to stop at 1.050 due to unfermentables, we are a third of the way with no signs of slowing down... it is the purple line, while as good as the blue, it is still very acceptable... (temp is holding nicely at 90F also... I think more important than heating is to settle and pitch within 72 hours, that purple one was 96 and the pH had started to nosedive after 72 but saying that, I still want to heat to 180, settle/cool to 90 and pitch...

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  • OK, after painfully waiting 8 hours for a 6kw element ran at half voltage, (1500w) to heat the next batch of molasses, I welded up some fittings and did a test run on the 1/4" steam eductor from aliexpress hooked to my unikeggle with 2 5500w elements making steam to heat 20 gal of water... it was fast, 30 degrees in just a few minutes... extremely loud... I mean in the room with a jet engine loud.... hopefully molasses is noise dampening...

    https://www.youtube.com/watch?v=L4LmK7E7_Ps

  • Our steam eductor is the same, deafening, it's so violent it rattles the mash tun, so loud you really can't have a conversation anywhere near it. It gets quieter once the mash viscosity thickens, so it probably will be quieter with a heavy molasses.

  • Looks good though, looks like you have some good mixing action going on too.

  • I use the hot backset from a run to thin the molasses (12 gallons backset, 12 gallons molasses) in my conical then let it settle. Works great and you don't have to boil water. I've never had a problem with bugs and I have let it sit for almost a week. I think by you using water that you end up with something that the bugs like.

    Also, I usually rack off after 2 days of settling. Not enough time for bugs to settle in.

    Timing a new wash around the stripping run has always worked for me.

  • Possibly the pH, if you have a pH pen, measure the pH after you mix the backset in. My rum backset it usually pretty darn acidic. pH 3-3.5 range if I am remembering correctly.

  • The timing with a stripping run definitely hods true.....

    Here are 2 mason jars, 3 days old, one with boiled (500ml each water and molasses nuked, and then 500ml more boiled water added) on the left and one with just boiled water, but unboiled molasses on the right.. there be serious bugs in that molasses... I will try to get the director of rum to get back to using backset... but it ain't happening overnight, I will do a bunch of tests like this with stirplates and even distill in the 2L lab still to compare flavor profiles with and without dunder..

    *note how much better the settling was, not sure if the heat or had some action happen in the boiling process that helped..

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  • Hold on one sec... they both initially got boiling water and microwave? Then you added tap water to the one on the right?

    Just trying to discern if it’s your water.

  • no, edited for clarity, only one on the left brought to boil with molasses in it... the other was just boiling water added to molasses, only got to 140 or so

  • edited February 18

    Impressively thermotolerant bugs, 140ish is right on the cusp of pasteurization temperatures. Realistically, you shouldn't have to go much higher than 160 for a few minutes, or 170 for a minute or so.

  • Can you try another jar test using sulfuric acid and boiling? Just to gauge the potential benefit to sedimentation? Easy to get a small quantity of sulfuric off Amazon, they even have it prime.

  • don't have any sulphuric laying around... but I did use the tiny 1/4" steam eductor and it ROCKED... 40 minutes at 11kw forcing screaming, highly active water molecules leaving the unikeggle at 8psi and hitting 330lbs of molasses raised it to 190 and added 30lbs....

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  • They don’t stand a chance at 190.

  • I need to hard pipe it or get a true steam rated hose, I spent the entire time standing back near the e-stop... only 8psi at 240F, but that noise scares the shit out of you... and it is an old craftsman 5/8" rubber garden hose...

    I have a 3/8" eductor but it wont fit through a 2" TC, however I have a drum with a 2.5" fitting, not sure how much better that will be or what the btu or bhp rating of these things are..

    I think I need to make an 8" end-cap with a PRV 2" fitting and a gauge fitting and use a HP clamp...

    Girl from the trendy coffee shop came by when we were testing it last night, I explained it as being a steam wand able to froth 20 gallons of milk in 10 minutes... I can't wait to try a bag of corn with this thing and start cold with enzymes!!! hell, I want to test it our on a homebrew mash!

  • and of course now my mind wanders back to the twin tube steam generators... if I made one that hung on the side of the tank, it could be hard plumbed.... I need more hours in the day...

  • @CothermanDistilling said: I will try to get the director of rum to get back to using backset... but it ain't happening overnight, I will do a bunch of tests like this with stirplates and even distill in the 2L lab still to compare flavor profiles with and without dunder..

    Yeah, what he said... this has been quite the adventure, and at this point now that we have weeded out a lot of the issue and have gotten back to the basics we started with, we will re-introduce things such as the hot stillage, but it absolutely needs to benefit the flavor of the product, and currently we don't have any lack of flavor :-)

    Dean Palmer - Director of Rum - Cotherman Distilling - Dunedin, FL

  • edited February 20

    You guys ever consider supplementing the molasses with cane sugar to vary the flavor profile?

    I spend a lot of time in old rum and sugar literature. What's incredibly obvious to me is, molasses is about as far from a constant as you can get. The molasses that would have been used a hundred years ago would have been dramatically higher in sugar content, as the refining technology was not nearly advanced as it is today. As sugar technology has improved massively, more centrifuges, more chemistry, more tech, higher yield of crystals, the nature of the molasses has changed. Blackstrap today is not anything like the blackstrap of yesterday, and this continues to change ... for the worse, not better.

    This kind of thing is going to translate into flavor and character. I'm not saying better or worse, I'm saying different character. I personally know, working with the Black Pearl products, the end rum from their high test (70-76% sugars) products is very different from their dark product (45-54% sugars), the total fermentables is going to have a pretty marked impact on the flavor, and I strongly believe this has to do with two factors - the underlying molasses flavor impact, and the pure ethanol yield impact.

    On the last part, by adding cane sugar to the molasses, increasing the fermentables and ethanol yield has the end result of dialing back the molasses flavor towards a more neutral profile, however, it's within the context of the molasses flavor profile you are working in. Obviously using a lighter colored high-test is going to have a mild profile already, so there is no real sense in dialing that back even further, but with a deeper flavored blackstrap, being able to dial that back by adjusting the fermentables, and not necessarily distilling it out at a higher proof.

    Either way, it seems to me that taking a modern molasses product, and increasing the fermentables with cane sugar, can get you back to what would have been a fairly typical molasses profile from decades back.

  • Good to hear another person say that. I've always figured I could approximate 250-year-old molasses with agricultural blackstrap and and white sugar. Of course, I like my rum rich in molasses flavor.

    Zymurgy Bob, a simple potstiller

    my book, Making Fine Spirits

  • Sure. Most modern processing takes it down to a very metallic tasting profile when producing modern blackstrap. Pretty much unpalatable.

    Don't know how anybody doing a single run on a pot still could ever render anything that would ever appeal to the wider market?

    StillDragon North America - Your StillDragon® Distributor for North America

  • We did it with 20-30% panela, which was a very expensive proposition, we want to get a baseline done on the highly affordable molasses and go from there... I did give @smaug a bottle each of our silver and cane vodka which are only separated by 183 vs. 190 proof of of the 24-plate still....... they were from when we were doing full wash heating in the still and letting settle overnight...

    We have about 10 different things we want to try in controlled experiments, but 2^10 is a big number... just working on the baseline for now, I want our hands on guy to have 100 washes under his belt before we tweak much......

    @grim said: You guys ever consider supplementing the molasses with cane sugar to vary the flavor profile?

    I spend a lot of time in old rum and sugar literature. What's incredibly obvious to me is, molasses is about as far from a constant as you can get. The molasses that would have been used a hundred years ago would have been dramatically higher in sugar content, as the refining technology was not nearly advanced as it is today. As sugar technology has improved massively, more centrifuges, more chemistry, more tech, higher yield of crystals, the nature of the molasses has changed. Blackstrap today is not anything like the blackstrap of yesterday, and this continues to change ... for the worse, not better.

    This kind of thing is going to translate into flavor and character. I'm not saying better or worse, I'm saying different character. I personally know, working with the Black Pearl products, the end rum from their high test (70-76% sugars) products is very different from their dark product (45-54% sugars), the total fermentables is going to have a pretty marked impact on the flavor, and I strongly believe this has to do with two factors - the underlying molasses flavor impact, and the pure ethanol yield impact.

    On the last part, by adding cane sugar to the molasses, increasing the fermentables and ethanol yield has the end result of dialing back the molasses flavor towards a more neutral profile, however, it's within the context of the molasses flavor profile you are working in. Obviously using a lighter colored high-test is going to have a mild profile already, so there is no real sense in dialing that back even further, but with a deeper flavored blackstrap, being able to dial that back by adjusting the fermentables, and not necessarily distilling it out at a higher proof.

    Either way, it seems to me that taking a modern molasses product, and increasing the fermentables with cane sugar, can get you back to what would have been a fairly typical molasses profile from decades back.

  • @grim said: Can you try another jar test using sulfuric acid and boiling? Just to gauge the potential benefit to sedimentation? Easy to get a small quantity of sulfuric off Amazon, they even have it prime.

    So I have been reading on the addition of sulphuric and want to give it a go... reading, it looks like .1% -.5% is the recommendation.. .3% with 360lbs molasses is about a pound... I am guessing that there are different strengths, would 1lb of this be the proper dosage? Is reagent grade good enough? " LabChem LC256602 Sulfuric Acid, 0.02N (0.01M), 1 L Volume"

  • OK, ordered some super strong 18M 98% sulfuric from a bio diesel place.. After reading the Sulfuric acid wiki, I think I will start off with less than half the amount and wear some serious safety eq.

    thoughts, @grim ?

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