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Molasses wash pH and stuck fermentations

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  • edited October 2018

    Let me try to see if someone mentions the pH target to shoot for, as opposed to the amount. For the first attempt, you'd want to slowly add while monitoring pH (basically titrate it in).

    If you overshoot, you are going to need a bunch of sodium hydroxide to compensate. No sense overshooting the acidity to just cause a different problem.

  • Our molasses starting pH (after water mix) is 5.4......

    The Production of Light Rum from Molasses (1946) says 4.5-4.7

    Ethanol Fermentation of blackstrap Molasses patent 2,295,150 (1942)says:

    The acidity for the thick mash depends on the acidity of the original molasses. The alteration in acidity should amount to about 0.5 pH, as one phase of the thick mashing operation is that of producing a change of equilibrium for the original constituents of the molasses that results in the precipitation of non-sugars. Thus, molasses usually has an original pH of 5.2 to 5.7, and this would be correspondingly reduced in thick mashing to pH values of substantially 4.7 to 5.2. The quantity of acid to be introduced can be determined as roughly that which will produce this shift of pH reading and which will effect an optimum sedimentation.

    So 4.9 would be a target..

    Interestingly, the Maza Gomez Thesis (1998) says:

    A lower pH will yield relatively higher amounts of alcohol, while the production of a good aroma is achieved between pH 5.5- 5.8.

  • @grim, definitely makes perfect sense. Grandad's blackstrap would have been good enough to put on hotcakes. Notwithstanding fermentation, it's really now only fit for livestock and fertilizer.

    Michael I know you may not have an optimal amount of floor space, but do you plan on incorporating any back blending by holding back a measure of previously distilled finished distillate to be added to the forthcoming batch?

    StillDragon North America - Your StillDragon® Distributor for North America

  • @Smaug said: grim, definitely makes perfect sense. Grandad's blackstrap would have been good enough to put on hotcakes. Notwithstanding fermentation, it's really now only fit for livestock and fertilizer.

    Michael I know you may not have an optimal amount of floor space, but do you plan on incorporating any back blending by holding back a measure of previously distilled finished distillate to be added to the forthcoming batch?

    once we get some more basic things done, yes... back at stuck fermentation after trying a new yeast... hopefully the sulfuric acid will help drop some things out, and interested to see if the other chemical additions (ammonium sulphate and calcium superphosphate) will help and possibly eliminate the need for the more expensive yeast nutrient.. which I have not come across in the reading yet... and I also like the 50/30/20 staggered fermentation that will allow us to use less yeast... been throwing a lot of molasses and labor down the drain lately...

  • @CothermanDistilling, your white rum by the way is one of the better ones (no bullshit) on the shelf. It has a good, clean mouth feel and I bet would make a lovely Mojito as the rum notes are very warm and inviting.

    Though the vodka is very clean, the rum notes (though very thin) are there. Not so much on the nose, but rather on the pallet. Somewhat reminds me of a Don Q esq highly filtered rum. Would be interesting to see how this would round out in a spent barrel? Rum notes are bullfrog tough and just not easy to make go away.

    StillDragon North America - Your StillDragon® Distributor for North America

  • @Smaug said: CothermanDistilling, your white rum by the way is one of the better ones (no bullshit) on the shelf. It has a good, clean mouth feel and I bet would make a lovely Mojito as the rum notes are very warm and inviting.

    Though the vodka is very clean, the rum notes (though very thin) are there. Not so much on the nose, but rather on the pallet. Somewhat reminds me of a Don Q esq highly filtered rum. Would be interesting to see how this would round out in a spent barrel? Rum notes are bullfrog tough and just not easy to make go away.

    Thank you... the Crockett's Reserve I gave you is pretty much that, in a spent whiskey barrel, but also with some toasted stave treatment.. We are making it better (in our own opinion) at fairly regular intervals... and we know we have much, much more to learn...

    I am sick as a dog these last few days, hope to have the full copper still in action this month with some improved ferments with the D022 tropical rum yeast.... the only one that fermented completely and at the proper speed was the one that went out of control and was at 97 degrees... the distillate was very different than our standard yeast, but tasty in it's own way........ the ones controlled to 91-92F fizzled out at only 25% fermented...

  • edited October 2018

    You guys aren't collecting and reusing yeast? We do with rum, even without clarifying. Even with flat bottom tanks, we sometimes just crash cool to let the yeast settle, and pump over the next wash on top of the yeast cake (at pitch temp, obviously).

    We've been having some pretty good luck, and yield, with the new protocol.

    Which is, 2 drums, one fancy/high test, one blackstrap, for a 2000l batch. 1kg of Lallemand RM. 1 pound of DAP staggered (1/3rd and 2/3rd sugar utilization), 1 pound yeast nutrient, at pitch. We are using 55g of fresh backset per batch and citric to drop to 5.0 to start. I was convinced I would have problems with a 24-25 brix starting point (approx 1.10sg), which is way higher than I'd ever run anything, but the last ferments were fairly fast and complete. Ending gravities were sitting around 1.01 at about 8-9 days total.

    Nice for us because each batch refills two 30 gallon bourbon dump barrels.

  • With the new yeast, we are attempting to reuse a few times..

    Hoping the acid addition will help drop stuff out of suspension, we add a similar percentage of molasses (25% of the volume), start at 1.12-1.125 and end at 1.050 if we are lucky..., and there is no sugar left in it... and a lot of sediment in the still after the run... planning on some tests in 1000ml graduated cylinders when the sulfuric arrives, may try citric, do you just add it dry?

    Also intrigued by arroyo's 'thick mash' method of 50/30/20 additions.

  • edited October 2018

    Dry citric, we buy it by the 50lb sack for pH adjustments. I'd like to use lactic but it's too expensive.

  • I have quote request out to bellchem for a few things, they were $26/gal for 36% sulfuric

    • Sodium Percarbonate 55# bag
    • Sodium Metasilicate 55# bag
    • Citric Acid - 55# bag
    • Calcuim Carbonate 55# bag
    • Calcium Hydroxide 55# bag
  • so I go to look for typical amounts of citric acid to add to molasses fermentation, and slap me silly, molasses fermentation is one of the ways they make citric acid...

  • OK, I did a small test with citric acid trying to copy Arroyo's 'thick mash' settling... Our molasses is already thinned some by the supplier down to 45% SAI sugar, so adding the 42.75% by weight of water took some reverse engineering with a jug of the 70% or so TSAI, we ended up deciding to use a 33% addition calculated by volume to compensate after doing some tests. I took 300ml of the 45% and added 100ml water and nuked it 2:35 in a beaker then verified it got to 80c(170f) and then put it in a 1000ml graduated cylinder. I did the same thing again but added 2 grams (0.4% by weight) of citric acid and the pH dropped from 5.05 to 4.55.

    after 24 hours the 400ml the non acidified had a settling line of 240ml, and the treated one was 230-235, which a tiny bit better, but quite high... I added another 100ml and gave the cylinders a swirl and will check tomorrow... (note, this is not final fermentation thickness, but about double that...

    I will do another test tomorrow with the 200ml of water added to 300ml of molasses, heated to 170 and add in the Ammonium Sulfate and Calcium super-phosphate that Arroyo mentions, but I think they are more for the yeast...

    I will do an additional test, one with 500ml of molasses and a 500ml of water, settle for 24 hours and then rack off the clear liquid and re-top off with water and settle again and then carefully measure the solids and measure... it is quite possible we need to upgrade our molasses or be willing to lose more...

  • The ammonium sulfate is a precipitating agent.

  • OK, thanks, I tested the existing graduated cylinders with adding both and reheating to 170 and not much better...

    I decided to do a new test with 300ml(407g) molasses and 300mL water and the .4-.45% citric for a .5 pH drop and .5% ammonium sulfate and .08% superphosphate, and then nuked to 170F. Wow, it dropped the sediment so much better(on the right), it was to the 130ml in 1 hour and got down to 110 ml in 2 hours... I took 300ml of clear off the top and put it in an erlemeyer with 500ml water and 1g of yeast, I will add the rest of the clear liquid in stages and see what happens...

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  • I decided to do a 100gal test, so took a 60 gal container and 360lb of molasses (~28gal)and steamed it to 180, let it sit for 10 min, added water to about 55gal, and stirred and took pH, 5.07.. I did not have bulk citric yet, but my 98% sulfuric had arrived, and that stuff is mean, I had safety glasses an gloves and tried to pour a little into the spinning molasses and it just bubbled and cooked and steamed... I know you add acid to water and not the other way, but even then, adding 50ml of 98% sulfuric to 900ml water was a exciting event! It heats it to 140 almost instantly... wow... it took 5 additions like that added to the 60 gallons to bring it down to 4.55... I added the ammonium sulfate and then the triple super phosphate(seemed like a lot of chemicals, but checked arroyo's numbers and my math twice and it was right...) I decided to let it sit overnight and tomorrow will add 50 gal water to the fermenter and pump in 25gal of the clear molasses and add yeast for 75 gallons, then when it starts fermenting good, will add 15 gal, and final 10 gal in stages... crossing fingers...

  • edited October 2018

    exciting!!

    EDIT: Exciting !!!

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  • You aren't worried about microbial fermentation in the held-back molasses? I like the staged fermentation, but would worry about it possibly being counterproductive if lone bacteria in the molasses are given a head-start.

  • Was Arroyo? it is only 6 hours for the first addition and 12 for the 2nd one if you can get it to work like his........

    I think the key is the recirculation... it helps expel co2, it keeps sugars available to yeast, and it keeps the temp uniform. here is a graph of the first 3-step... nearly done in 48 hours.. I was on with the recirculation only for a brief periods, probably recirculated 5% of the time, if that. Next time I should be able to go 100% and have a cooling system integrated into the recirculation system that will hold the 91 degrees spot on.....

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  • On the molasses side of things, even thought the molasses settled out like a rock with the ammonium sulfate and acid, I am pretty confident that we need to upgrade from the 'blackstrap' (as @smaug said, not your grandad's anymore, lets just call it 'feed grade') to the 'refiner's grade'... and at what looks to be a 20% increase in cost of the cheapest part of rum production... I just can't get it one tote at a time, I need to make room and get 15-20 totes worth delivered by a tanker...

  • edited November 2018

    @grim said: Which is, 2 drums, one fancy/high test, one blackstrap, for a 2000l batch. 1kg of Lallemand RM. 1 pound of DAP staggered (1/3rd and 2/3rd sugar utilization), 1 pound yeast nutrient, at pitch. We are using 55g of fresh backset per batch and citric to drop to 5.0 to start. I was convinced I would have problems with a 24-25 brix starting point (approx 1.10sg), which is way higher than I'd ever run anything, but the last ferments were fairly fast and complete. Ending gravities were sitting around 1.01 at about 8-9 days total.

    This is a newbie question - apologies in advance. I'm using Lallemand RM & DAP, what's the yeast nutrient please, as I thought DAP was the yeast nutrient? (I once forgot the DAP to my cost ...)

    Also, in a batch of 4 ferments, I re-use 20% backset each time i.e. the first ferment of 4 has additional water instead of backset. I've found I have always had to raise the pH to be in the 5.5 to 5.8 pH range (which the sales guy from Lallemand recommended to me for the start of a fermentation). My BRIX start on ferment 1 is about 20, but I find this rises on ferments 2,3 and 4 - I had presumed due to the unfermentable sugars in molasses which I'm recycling. By the time I get to ferment 4, the FG is up to 1.04. Am I doing something wrong, because I've never managed a FG of 1.01? I've also pitched all the DAP at the start, not sure if that's a factor? My ferments finish in about 5 days.

  • DAP is a nutrient for yeast, but not the only one commonly used... things like Fermax and Fermaid K have DAP and dead yeast cells and other things... ammonium sulfate and triple super phosphate also can bu used for nutrients.. many nutrients do double duty, the ammonium sulfate is (NH4)2SO4, and supplies nitrogen as well as helping to precipitate solids out before fermentation

    you mention 'unfermentable sugars' being in your backset.. I think you will find that 'unfermantable solids' is a better term... this explains you high final gravity... they are solids, not necessarily sugars...

  • edited November 2018

    The yeast nutrient we use doesn't contain DAP. We generally use the highest quality nutrient up front, followed by staggered DAP additions later. Not sure who said it, but think of DAP like potato chips - nutrient, but lower in quality/comprehensiveness, higher in calories.

  • I may have missed it in an earlier post but why are you adding ammonium sulfate to the mix? This is just the ammonia salt of sulfuric acid. Your adding in more sulfur to the mix and changing the pH after adding the acid.

  • Some guy named rafael arroyo mentioned doing it in 1941... so I figured I would give it a try...

    Seriously, though, it works, and I go for a total PH drop of .5, and get a good sedimentation and what I think is a good fermentation that gets me good rum at less than $2 per proof gallon material cost.

  • It’s still current tech, btw

  • Low pH and heat are good at denaturing proteins. I expect that is what you are doing with the denatured proteins aggregating and precipitating out of solution. I've never worked with molasses and this is going to be a nub question, do you need to remove the proteins from molasses to get a good ferment?

  • Protein as in the nutritional variety? There is no protein in molasses. There is however ash content. Ideal material has the lowest ash content.

    StillDragon North America - Your StillDragon® Distributor for North America

  • we are trying to switch to a higher grade, we want refiners vs feed grade, and our current supplier needs us to get on a contract to get it, which is not a big deal, we will take 1 tanker a year(26 tons), it seems that the good stuff is getting more scarce?

  • Yeah that's because the live stock grade makes all the money. The "rum" grade is just not occupying enough space at the moment. But it's coming.

    StillDragon North America - Your StillDragon® Distributor for North America

  • Putting a comment here due to hearing stuff form another distiller and our plan to move to refiners grade...

    Problems with this season's 'Refiners grade Molasses' include difficulties pumping with on-truck pump and with flavor and yield... entire tanker truck sent back as unacceptable...

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