Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Sugar, and all about sugar washes. Where the primary ingredient is sugar, and other things are just used as nutrients.

Moderator: Site Moderator

User avatar
VLAGAVULVIN
Trainee
Posts: 862
Joined: Tue Feb 06, 2018 4:52 am
Location: Western Urals

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by VLAGAVULVIN » Sun Oct 25, 2020 5:53 pm

Definitely, there's a way easier to make the yeast happy, guys. At least, easier for me with my rare sugarwashes.

For 4kg of white sugar I take some remains of groats (like cornmeal, rice, barley grits etc.) and cook them in my rice cooker, say 200-400g at all (could mix 2-3 groats together).

So, I start fermenting that "kasha" only (+ some water) with koji Angel stuff. The next day I add my inverted sugar and the rest of water accordingly. About 1kg of sugar per 5 liters of water. In a week it's done.

In that way, I'm not dependant on cows, their urea, dap, ipsum etc. ;)

Never make banana brandy. And never ferment potatoes: better make banana brandy... Oct.20, 2019


Watching your run is making me lazy (c) James LaBrie

User avatar
shadylane
Site Donor
Site Donor
Posts: 7071
Joined: Sat Oct 27, 2007 11:54 pm
Location: Hiding In the Boiler room of the Insane asylum

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by shadylane » Sun Oct 25, 2020 6:15 pm

That sounds like a good recipe :thumbup:
Could you tell us more about it here, so it doesn't get lost

viewforum.php?f=11

User avatar
VLAGAVULVIN
Trainee
Posts: 862
Joined: Tue Feb 06, 2018 4:52 am
Location: Western Urals

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by VLAGAVULVIN » Sun Oct 25, 2020 9:22 pm

shadylane wrote:
Sun Oct 25, 2020 6:15 pm
Could you tell us more about it here, so it doesn't get lost
Sure, man :)

Never make banana brandy. And never ferment potatoes: better make banana brandy... Oct.20, 2019


Watching your run is making me lazy (c) James LaBrie

zapata
Distiller
Posts: 1531
Joined: Fri Jul 07, 2017 1:06 pm

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by zapata » Mon Oct 26, 2020 3:24 am

On a purely practical level, we have many people over years (myself included) seeing good results from feeding yeast with yeast. We have commercial sources that use yeast for quite expensive yeast supplements. On a laboratory scale, YEPD (Yeast Extract Peptone Dextrose) is the go to media from researchers to yeast producers, and it's basically a fancy yeast bomb with corn sugar. Feeding yeast dead yeast is a thing, it's real, and it's has solid theoretical support and proven practical results.
VLAGAVULVIN wrote:
Sun Oct 25, 2020 5:44 am
P.S. The cooked yeast nitro bomb would easily contain some free form BCAAs, too. The point is: any significant qty. of them or not...
You know, that is a good point and I have wondered that myself. Many times. Never enough to actually look into it. So... let's do that, and let's pretend the yeast in a yeast bomb is like nutritional yeast?

Nutritional yeast has 8 grams of protein per 15 gram (1/4 cup) serving, so .53 mg protein / gram. Of the protein, in mg/g of protein it has:
Valine: 49 mg / g of protein 398 mg total in 15 grams (1/4 cup)
Isoleucine: 37 mg / g of protein 296 mg total in 15 grams (1/4 cup)
Leucine: 64 mg / g of protein 512 mg total in 15 grams (1/4 cup)
Phenylalanine 33 mg / g of protein 264 mg total in 15 grams (1/4 cup)
Methionine 14 mg / g of protein 112 mg total in 15 grams (1/4 cup)
(plus some others that I don't think ever play Ehrlich's game)

My BCAA supplement has in one heaping teaspoon (5.75 grams):
Valine: 500 mg / g of AAs (2,500 mg per serving)
Isoleucine: 250 mg / g of AAs (1,250 mg per serving)
Leucine: 250 mg / g of AAs (1,250 mg per serving)

So on a bulk basis it's as much as 18x more potent, and the ratios are different. 1 gram of BCAA supplement has 25% more valine than a 1/4 cup of dry yeast!

Questions remaining.
1. Are the Amino Acids in yeast "free" like they are in the powder?
Hypothesis, I doubt it. There's a century of experiments of dosing ferments with pure BCAA's and getting fusels, but I've never seen any analysis on the AA profile of typical feedstock causing high fusel yields. And from sour mashing to dunder it's not like supplementing ferments with yeast is a new thing so I suspect some of us would know if the AA profile of feedstock mattered much. Also, boiling a yeast bomb may empty the cells, it will denature proteins, but that just scrambles then it doesn't chop them up neatly into individual AA. I suspect at most AA in a yeast bomb are in the form of scrambled protein soup.

2. Are BCAA's even going to supply yeast with nitrogen they need?
Hypothesis, maybe not as much as other sources. For one, if the ehrlich pathway eats the BCAA's and makes fusels then they aren't there for the yeast anymore. For another, ammonia salts are super simple and just floating by freely, would a yeast really break down a protein to get to an AA to break it down and rearrange it if it already has the components?

3. Are yeast bombs even meant to supply amino acids? I would say no, that a yeast bomb supplies minerals, micro-nutrients, lipids and the like. It's less about feeding them what they need to metabolize and more about feeding them what they literally make themselves from. Sure, a yeast bomb contains some BCAA's, but only about a gram diluted into the whole wash. But they do have 100% of all the other "stuff" that it took to make a big pile of yeast bodies.

So, still some questions, but I'm less concerned about BCAA's in yeast bombs than I was before, thanks. Without balancing the equations it looks like at worst a yeast bomb might add as much as a ml of fusel oil to a wash from the ehrlich pathway. (I'm a nerd, so I'm sure I will do that at some point, but for now I need more coffee)

User avatar
VLAGAVULVIN
Trainee
Posts: 862
Joined: Tue Feb 06, 2018 4:52 am
Location: Western Urals

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by VLAGAVULVIN » Mon Oct 26, 2020 3:50 am

zapata wrote:
Mon Oct 26, 2020 3:24 am
Also, boiling a yeast bomb may empty the cells, it will denature proteins, but that just scrambles then it doesn't chop them up neatly into individual AA. I suspect at most AA in a yeast bomb are in the form of scrambled protein soup.
Well. The yeast cell has "eaten" some protein. What is the metabolite of this absorption?

[I hope there's no chain reaction when some start AAs make more AAs thru the cells' "guts" and thus fusels make more fusels...]
Don't read this bullshit within [..] :mrgreen: The best way here is weak ferment / low starting gravity. The sooner stops = the better.

zapata wrote:
Mon Oct 26, 2020 3:24 am
For another, ammonia salts are super simple and just floating by freely, would a yeast really break down a protein to get to an AA to break it down and rearrange it if it already has the components?
Based on the general principles of metabolism on this planet, living yeast cells will follow the path of the least energy consumption. :roll:
But still they need all those prots from "the soup", too. What do they do with prots?.. For instance, my own cells need not only carbs. They need prots and they are able to release free amino acids into the general bloodstream.

Never make banana brandy. And never ferment potatoes: better make banana brandy... Oct.20, 2019


Watching your run is making me lazy (c) James LaBrie

User avatar
Evil Wizard
Site Donor
Site Donor
Posts: 99
Joined: Sun Jan 08, 2017 3:21 pm
Location: The Rock, Canuckistan

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by Evil Wizard » Wed Oct 28, 2020 3:16 pm

Hey Zapata honey, can you whip me up some propanol and butanol real quick? I got a hankering to esterify some carboxylic acids since my flavour house won't sell me basic esters to train my nose.
Work is the curse of the drinking class. "Would you like some water?" "No thanks, I'm Irish."

Louchebag Absintheur, Apostolic Alcoholic, Whisky Icarus, Bathtub Alchemist.

Started 2005, went Pro 2017. Federal Excise 51-SL-262.

zapata
Distiller
Posts: 1531
Joined: Fri Jul 07, 2017 1:06 pm

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by zapata » Thu Oct 29, 2020 2:24 pm

Lol, sure. Or if you're serious, carolina.com sells both, and amyl too.

Stibnut
Novice
Posts: 33
Joined: Thu Apr 16, 2020 10:03 pm

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by Stibnut » Sun Nov 01, 2020 3:30 pm

VLAGAVULVIN wrote:
Sun Oct 25, 2020 8:49 am
By the way, I'm playing now with that Swiss Calculator (thanks to Stibnut again)... and still cannae make it out how the Scotts do get their esters and fatty acids. The first are killed by stripping, the rest - by spirit runs. Newly formed during the 2nd run reboiling? OK for some esters, but acids, like butyric, isovaleric and so forth? They cheat somehow, don't they?
There are a couple of factors here to think about.

One of the things I learned from this simulator is that it's very important not to throw out foreshots if you're doing anything besides a neutral. The fact that esters are hydrophobic tends to push them out from a wash far faster than you might expect from their boiling points, assuming you're using a pot still. Not only that, but the hydrophobicity increases with the length of the carbon chain, and we also tend to perceive longer-chain esters as better smelling and can smell them at smaller concentrations. The result is that esters tend to come over in the reverse order to their boiling points - so the long-chain ones disproportionately come over very early on.

But this is only true of stripping runs on pot stills. In spirit runs, longer esters come out in the hearts. At low wine ABVs, hydrophobic molecules get less of a ‘push’ from water and more of a ‘pull’ from the ethyl group of ethanol, so their volatility behavior has more to do with their boiling point.

In the simulator with rectification = 0 and ABV = 8%, plug in ethyl acetate and ethyl caprate (or caprinate, a C10 fatty acid). You'll see the ethyl caprate comes over far more rapidly, so that it's almost all in the distillate before even half of the ethyl acetate is there.

Now dial the ABV up to 40%. Watch how most of the ethyl caprate comes out in the first half of the hearts, rather than in the heads. At the beginning of the run, it starts out less volatile than ethanol, but it becomes more volatile as the ABV in the still goes down. So the heads odor/taste is dominated by acetaldehyde and ethyl acetate, but the proportion of pleasant longer-chain esters increases right around the time you’d want to make your cut. This effect is strongly improved by adding a little bit of rectification; just increasing from 0 to 0.3 makes a huge difference in separating acetaldehyde and ethyl acetate from the fruitier/floral esters. This is why we go slow during a spirit run.

The other thing to keep in mind is that the human nose is - despite being one of the worst in the mammal world - extremely sensitive to certain types of compounds, including longer esters and some other things like terpenes and longer aldehydes. Odor thresholds here are in the 1 ppm range, if even that. But we’re less sensitive to acetaldehyde and ethyl acetate - ballpark 10 ppm for the first and 100 ppm for the second. So the separation doesn’t have to be all that great to get good results.

I’ve gained a lot of appreciation for the sensitivity of the nose at my job. The only beverage product we produce is neutral grain spirits, and when done well the product is incredibly pure, with generally < 5 ppm propanol and methanol and no other major congeners even detectable by GC. The most important test we do on that isn’t GC analysis, it’s diluting a sample to 20% ABV in a tulip glass and taking a sniff. Sometimes there’s still an off odor that causes it to be downgraded to hand sanitizer/cosmetic grade, and although I’ve spent hours poring over GC chromatograms trying to identify any little peak that might correspond to bad odor, I’ve never found anything. The nose is quite a bit more sensitive than a GC to a wide variety of compounds.

I also do think some esters are formed in the low wines between distillations or during the spirit run. As long as you’re stripping down well into the “wet dog”/”stinky socks” tails, you’ll pick up enough fatty acids to form some esters. Those smells come from short/medium chain fatty acids (and not fusels), and these have lovely odors ranging from B.O. to rancid meat/butter/cheese to vomit to barnyard animals. Caproic, caprylic, and capric acids (C6, C8, C10) are all named after goats for a reason! But if they form esters, those esters are usually nice and fruity and prone to coming out in the hearts of a spirit run.

Stibnut
Novice
Posts: 33
Joined: Thu Apr 16, 2020 10:03 pm

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by Stibnut » Sun Nov 01, 2020 3:54 pm

zapata wrote:
Mon Oct 26, 2020 3:24 am
On a purely practical level, we have many people over years (myself included) seeing good results from feeding yeast with yeast. We have commercial sources that use yeast for quite expensive yeast supplements. On a laboratory scale, YEPD (Yeast Extract Peptone Dextrose) is the go to media from researchers to yeast producers, and it's basically a fancy yeast bomb with corn sugar. Feeding yeast dead yeast is a thing, it's real, and it's has solid theoretical support and proven practical results.
VLAGAVULVIN wrote:
Sun Oct 25, 2020 5:44 am
P.S. The cooked yeast nitro bomb would easily contain some free form BCAAs, too. The point is: any significant qty. of them or not...
You know, that is a good point and I have wondered that myself. Many times. Never enough to actually look into it. So... let's do that, and let's pretend the yeast in a yeast bomb is like nutritional yeast?

Nutritional yeast has 8 grams of protein per 15 gram (1/4 cup) serving, so .53 mg protein / gram. Of the protein, in mg/g of protein it has:
Valine: 49 mg / g of protein 398 mg total in 15 grams (1/4 cup)
Isoleucine: 37 mg / g of protein 296 mg total in 15 grams (1/4 cup)
Leucine: 64 mg / g of protein 512 mg total in 15 grams (1/4 cup)
Phenylalanine 33 mg / g of protein 264 mg total in 15 grams (1/4 cup)
Methionine 14 mg / g of protein 112 mg total in 15 grams (1/4 cup)
(plus some others that I don't think ever play Ehrlich's game)

My BCAA supplement has in one heaping teaspoon (5.75 grams):
Valine: 500 mg / g of AAs (2,500 mg per serving)
Isoleucine: 250 mg / g of AAs (1,250 mg per serving)
Leucine: 250 mg / g of AAs (1,250 mg per serving)

So on a bulk basis it's as much as 18x more potent, and the ratios are different. 1 gram of BCAA supplement has 25% more valine than a 1/4 cup of dry yeast!

Questions remaining.
1. Are the Amino Acids in yeast "free" like they are in the powder?
Hypothesis, I doubt it. There's a century of experiments of dosing ferments with pure BCAA's and getting fusels, but I've never seen any analysis on the AA profile of typical feedstock causing high fusel yields. And from sour mashing to dunder it's not like supplementing ferments with yeast is a new thing so I suspect some of us would know if the AA profile of feedstock mattered much. Also, boiling a yeast bomb may empty the cells, it will denature proteins, but that just scrambles then it doesn't chop them up neatly into individual AA. I suspect at most AA in a yeast bomb are in the form of scrambled protein soup.

2. Are BCAA's even going to supply yeast with nitrogen they need?
Hypothesis, maybe not as much as other sources. For one, if the ehrlich pathway eats the BCAA's and makes fusels then they aren't there for the yeast anymore. For another, ammonia salts are super simple and just floating by freely, would a yeast really break down a protein to get to an AA to break it down and rearrange it if it already has the components?

3. Are yeast bombs even meant to supply amino acids? I would say no, that a yeast bomb supplies minerals, micro-nutrients, lipids and the like. It's less about feeding them what they need to metabolize and more about feeding them what they literally make themselves from. Sure, a yeast bomb contains some BCAA's, but only about a gram diluted into the whole wash. But they do have 100% of all the other "stuff" that it took to make a big pile of yeast bodies.

So, still some questions, but I'm less concerned about BCAA's in yeast bombs than I was before, thanks. Without balancing the equations it looks like at worst a yeast bomb might add as much as a ml of fusel oil to a wash from the ehrlich pathway. (I'm a nerd, so I'm sure I will do that at some point, but for now I need more coffee)
Thanks for all your information about the Ehrlich pathway, zapata! I didn't know as much as i should about it - I just had a vague knowledge that some amino acids get broken down into fusels. This makes me wonder what the odor and taste of non-BCAA Ehrlich products are, and whether any of the ones with say nitrogen or sulfur side chains carry over into the distillate. I do know that 2-phenylethanol comes from phenylalanine and has a nice floral odor.

My understanding is that yeast are almost as lazy with proteins as they are with sugars: they insist on eating only small oligopeptides or free amino acids and don't bother breaking down whole proteins, whether in their normal conformation or denatured. Is this correct? If so, boiled yeast wouldn't contribute all that much to their nitrogen diet, but would still be a rich source of vitamins, minerals, sterols, etc.

Related - can you think of an experiment you would like to see regarding fusel production? I have yeast extract, Fermaid K, DAP, and ammonium chloride for nitrogen sources, and I'm willing to sneak two or three samples from stuff I make at home onto the work GC, passed off as fusel draws. Right now I'm running an experiment with three different OGs using glucose as the sugar, EC-1118 as the yeast, and holding nitrogen and other nutrients constant. I'd like to do a follow-up that looks at a different factor, probably the nitrogen source. I was thinking yeast extract vs. DAP with addition of the same amount of B-vitamins, magnesium, calcium, and zinc to each. But if you have any other ideas I'm all ears!

zapata
Distiller
Posts: 1531
Joined: Fri Jul 07, 2017 1:06 pm

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by zapata » Sun Nov 01, 2020 8:55 pm

Dude, you just hit on exactly what I've been reading and thinking about this week, including phenylethanol. Along that path I was thinking of trying to spike some phenylalanine in a kale wash to get some phenylethanol production. Might be tastey with the floral note from kale (carotene/oid derived "rose ketone"?). Phenylethanol even looks a bit like damescenone, yeah?
phenylethanol damascenone.png
I haven't really dived into it yet, so if you're going to experiment on anything, that seems interesting. It would be fun to think of a not-ethanol alcohol in such a positive way. Could be well known, but it's a new idea to me. And it's hopefully noticable to the naked nose, so the lab time might be wasted on it? Although... is there good relative volatility data on phenylethanol? It's got a high bp, but is reported in rum and other spirits, but how does it fractionate?

There is a lot of literature on the other alcohols though, it seems pretty well sorted. Whisky Science, a Condensed Distillation (plus, what a clever title for such a nerdy book, amiright?) has a good summary with references which pretty much boils down to optimal pitch rate (which may vary from malt to bourbon to beer) and yeast health, temp, pH, and enough available nitrogen should minimize fusels. But like most things on fusels and BCCAs it mostly skips over phenylalanine and pheylethanol. It's probably worth quoting slightly abbreviated:
Higher alcohols are also produced by yeast, and these are important flavor
congeners. The main pathway for their synthesis is the Ehrlich pathway... An alternative
pathway involves pyruvic acid as a precursor... This latter
pathway occurs in amino acid deficient conditions, and is the main pathway for
the production of 1-propanol.

The branched alcohols active amyl alcohol, isobutanol, and isoamyl alcohol are
produced through the Ehrlich pathway from the branched amino acids isoleucine,
valine, and leucine, respectively. Branched alcohols are also formed as byproducts
of branched amino acid synthesis during the exponential growth stage of fermenta-
tion.
The amount and distribution of higher alcohols depends on temperature and pH.
Table 5.1 shows the effect of varying temperature in an open top fermenter from
20 ◦ C to 35 ◦ C. The higher alcohol content of all species is greatest at 30 ◦ C. At
20 ◦ C, the total abundance is the least, but some species are more abundant at 20 ◦ C
than at 35 ◦ C. The maximum higher alcohol abundance occurs when the pH is close
to 6.0, and the abundance is least when the pH is 4.0.

Malt distillery fermentations use very high pitch rates compared to brewery
fermentations: 2 × 10 7 vs 6 × 10 6 cells/mL, respectively. Experimental data
shows that increasing the inoculation level increases total higher alcohol production, leaving the proportions of alcohol species essentially unchanged. However, increased inoculation rate beyond distillery normal does reduce medium chain fatty acids (decanoic, octanoic, and dodecanoic) and their associated ethyl esters.
The typical distillery pitch rate of 2 × 10 7 empirically maximizes the production of
these compounds. Ramsay and Berry [678] speculate that the reason for this fatty
acid trend is the abundance of unsaturated fatty acids (lipids) supplied to the wash
by the inoculum. Commercial malt distillery inocula are typically aerobically grown, and so have an abundance of unsaturated fatty acids and sterols. Fatty acid production is diminished by the concentration of unsaturated fatty acids. This might not apply to bourbon and rye fermentations, on the grain, since the mash in
this case already has an abundance of lipids. According to Willkie and Prochaska,
Seagram, the inoculation rate for bourbon is 4 − 6 × 10 6 cells per mL of mash at a
minimum. Even accounting for the volume fraction of solids in a mash, this
inoculation level is closer to brewery levels than to malt wash levels.

Tables 5.3 and 5.4 show the results of experiments by Reazin, Scales, and
Andreasen of Seagram. The experiments compared five different mashes,
with the additions of radioactive threonine and isoleucine. The most striking
result in Table 5.3 is the observation that low free amino nitrogen (FAN) mashes
produce high levels of isoamyl alcohol. Guymon, Ingraham and Crowell
developed a hypothesis for this phenomenon known as the “keto acid overflow
theory”. It recognizes that yeast may form certain amino acids from corresponding α-keto acids and nitrogen. In nitrogen-deficient conditions, the keto acids accumulate (overflow). Their increased abundance leads to an increase in fusel alcohols by the Ehrlich pathway. The majority of the radioactivity due to isoleucine occurs as active amyl alcohol by the Ehrlich pathway (Figs. 5.2 and 5.3). In contrast, on the order of 10% of
threonine radioactivity forms propanol. Depending on mash, a substantial portion
appears as ethanol or active amyl alcohol. The appearance of radioactive ethanol is
attributed to the enzyme thronine aldolase which converts threonine into glycine
and acetaldehyde, and the aldehyde can be converted to ethanol with alcohol
dehydrogenase (XIII in Fig. 5.1). The appearance of threonine radioactivity as active
amyl alcohol occurs in nitrogen-deficient (low FAN) mashes and is due to the α-
ketobutyrate to α-keto-β-methyl-valerate reaction in Fig. 5.3.
But Fermented Beverage Production has this more concise summary, and a teasing phenylethanol blurb:
Higher Alcohols
Higher alcohols are produced from the carbon skeletons of amino acids. They may arise by the
decarboxylation and deamination of amino acids present in the wort or by a biosynthetic
route using the amino acid biosynthetic pathway of the yeast (Figure 2--4). Both these routes may
occur in the same fermentation, with a switch from the degradative route to the biosynthetic
route occurring when the amino acids in the wort have been metabolized. In general, condi-
tions that favor a high growth rate tend to stimulate the level of higher alcohol production.
These parameters include an elevated temperature, high inoculum levels, aeration of the
medium, and replacement of sugars such as maltose by glucose. These general effects will
increase the levels of all higher alcohols present in the medium; however, the levels of individual
higher alcohols can be manipulated by altering the amount of the corresponding amino acid in
the wort or must, or by genetically manipulating the organism so that producers may control the
amount of a given amino acid or higher alcohol.

This can be advantageous since certain amino acids induce a distinctive flavor; for example,
phenylalanine stimulates phenyl ethanol production, a higher alcohol that gives a roselike
aroma.
The bold part is what caught my eye, but in the spirit of the OP, let's highlight a different part for a second "replacement of sugars such as maltose by glucose." Sounds like a technical way to say "sugar bite" is real.

Anyway, so far as general nitrogen and amino digestion, Fermented Beverage Production summed that up pretty well too:
Utilization of Nitrogen Sources
S. cerevisiae can metabolize a number of nitrogen compounds. It can assimilate ammonia
readily through active transport and can grow well with ammonium as the sole source of nitro-
gen except for a few vitamins such as biotin and nicotinamide. Urea is also a good source of
nitrogen and is converted to ammonium within the cell (but you might not want it for other reasons - zapata). Nitrate and nitrite cannot be used. All a-amino acids can be taken up readily, as can small peptides. Proline can only be used under aerobic conditions, as its metabolism involves an oxidase-catalyzed step. The organic com-
pounds vary greatly in their ability' to sustain growth as single compounds, but mixtures of
amino acids tend to support the best growth. Yeast has no extracellular protease activity and
so cannot utilize large peptides or proteins.
In industrial practice, as media tend to contain a
wide range of amino acids and ammonium, and in some cases urea may also be added, availabil-
ity of nitrogen is not usually a problem. In fact, the amount of assimilable nitrogen may be
deliberately restricted to give just enough yeast growth. This tends to improve the efficiency of
conversion of sugars to ethanol and CO 2 and makes the resultant alcoholic liquor less sup-
portive of bacterial growth.
All that said, and I know I'm in a neutral thread, but the implications for flavor products in all this are more interesting to me. For neutral, of course start with the best wash you can, but like the plant you work at, if you want a neutral you're gonna have to make it in the still anyway, so worrying about a few ml's here and there may be unnecessary. You're gonna need a tall column, lots of reflux, strict cuts, more than one run through, and optimally a neutralization step as well, even if you start with the cleanest wash ever made.

User avatar
VLAGAVULVIN
Trainee
Posts: 862
Joined: Tue Feb 06, 2018 4:52 am
Location: Western Urals

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by VLAGAVULVIN » Mon Nov 02, 2020 1:42 am

Stibnut wrote:
Sun Nov 01, 2020 3:30 pm
There are a couple of factors here to think about.
Stibnut, thanks for your good write up. Yepp, I’m with you on esters and other things. Low alco contents of the “beer” turn many things upside down. And that "Begleitstoffesimulator" just illustrates it well. For instance, during the stripping run the most of fusels leave the pot before its temp gets 93 centigrade. Here’s my tip to get clean but unfortunately "late-headless" distillate in 3 runs.

And I could share how I do get them fatty acids. High boiling thangs...

Here is my build for the 2nd run / classic distillation. As you see, I have a bladder above there (before the condenser). It works more like Scottish purifier than American thumper.

There's an adiabatic expansion happens in it. And kind of flegma is formed. All run long the AbV of this liquid stuff is in average 10% lower than I get it from the product output. In the beginning of the run there's a lot of fusels concentrated inside (I have to drain them out constantly). So, I’m getting my heads from the spout and the same time – the concentrated fusel funkies (thru that purifier’s separate ball valve).

I drain it the last time during early tails getting. When my tails are done then the most of the purifier’s contents are “dramatically changed” to fatty acids. Very low alco, not fusels but fine bread-ish (hello to some furfural?..) and honey odor, acidic pH. I proof them up to 50-60% AbV and they get matured separately rather fast on oak staves. Then I drop them back to the main product.

zapata wrote:
Sun Nov 01, 2020 8:55 pm
and optimally a neutralization step as well, even if you start with the cleanest wash ever made.
Acidity reduction?

Never make banana brandy. And never ferment potatoes: better make banana brandy... Oct.20, 2019


Watching your run is making me lazy (c) James LaBrie

zapata
Distiller
Posts: 1531
Joined: Fri Jul 07, 2017 1:06 pm

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by zapata » Mon Nov 02, 2020 11:43 am

Vlagavulin, that 2nd link is one I missed and super interesting, thanks for linking it here. Scottish style purifiers are rare in the hobby and hands on experience is virtually non-existent, definitely following that and will discuss it there.

And yes, by neutralization I mean making the low wines slightly basic to break esters and prevent in situ formation. As much as recovering the ethanol it just seems to give a constant makeup in the pot for the still to deal with.

User avatar
Corsaire
Site Donor
Site Donor
Posts: 1017
Joined: Tue Jun 20, 2017 1:20 pm
Location: Belgium

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by Corsaire » Mon Nov 02, 2020 11:48 am

So what's in those purifiers and how does it work?
I asked about them earlier but was told they were just slobber boxes. Interested to hear your take on it Vlagavulvin.

User avatar
VLAGAVULVIN
Trainee
Posts: 862
Joined: Tue Feb 06, 2018 4:52 am
Location: Western Urals

Re: Neutral 'Bite' - Unstable Fermentation Temp, Invert Sugar or Simple Syrup?

Post by VLAGAVULVIN » Tue Nov 03, 2020 11:15 pm

Corsaire wrote:
Mon Nov 02, 2020 11:48 am
So what's in those purifiers and how does it work?
I asked about them earlier but was told they were just slobber boxes. Interested to hear your take on it Vlagavulvin.
Hey! We picked up our stools and went over there with all those purifiers :roll:

Never make banana brandy. And never ferment potatoes: better make banana brandy... Oct.20, 2019


Watching your run is making me lazy (c) James LaBrie

Post Reply