Worry about pectinase + fruit increasing methanol yield?

[helmingstay]

The only "well-informed" post i could find to these specific ends was the following unanswered and very good question:

"Can the galactose residues in pectin be demethylated without hydrolysis of the polymer during fermentation? Various sources of practical advice imply a different answer to this question."

As a brief review, pectin is a branched structural polysaccharide. The backbone is composed of D-Galactose, and "in nature, around 80% of carboxyl groups of galacturonic acid are esterified with methanol" ( http://en.wikipedia.org/wiki/Pectin... another reference is the paper titled "Determination of the degrees of methylation and acetylation of pectins using a C18 column and internal standards" by LEVIGNE, 2002 ).

Pectinase dismantles the pectin's "structure" and makes it available for fermentation as methylated galactose and other sugars. By removing the structure, I get more fruit juice, but I also increase fermentable methylated galactose, right? Is it enough to worry about, or just increase the foreshots cut?

Again from wikipedia:
"Typical levels of pectin in plants are (fresh weight):
apples, apricots approx. 1%
oranges 0.5 - 3.5%
carrots approx. 1.4%"
In addition, sugar beets, potatoes and pears seem to have more backbone-type pectin. This perhaps leads to overall higher levels of methylation and the poisoning of countless russian homedistillers?

I'd be happy to do some research on the 10+ pounds of apples I'm starting soon. I was thinking that an NMR should be able to resolve the two in the foreshots if the methanol is of sufficient quantity to be a nuisance ( I can rent time at an old NMR at the university pretty cheap ).

Any thoughts?

[junkyard dawg]

most of that is over my head...


I do use pectic enzyme and I do distill fruit washes, mostly apple and grapes... Learn to use your senses and make generous fores/heads cuts and you will have no problems with hangover inducing spirits.... fruits make great spirits, just make good cuts and you can make some fine likkers.

[goose eye]

aint smart enough to figure out most of your words but if i was a betin man id be betin it a hole bunch of thangs that is killn them ruskys dead.
mifa is big in the likker makein over yonder

lead in there outft
medical testin alcohol bein cut down an mixed - greed -
insecticides fungicides
drinkin good likker made rite every nite


when in dout
pour it out

so im tole

[theholymackerel]

I've been under the impression that we were not to use pectinase because it would cause there to be more methanol.

Any "good" information would be very welcome.

[The Chemist]

I vote for "just increase the foreshots and don't worry about it."

Also, GC/MS (or just GC, FTM) will be more useful, and cheaper, than NMR.

[helmingstay]

most of that is over my head...
Learn to use your senses and make generous fores/heads cuts and you will have no problems with hangover inducing spirits.... fruits make great spirits, just make good cuts and you can make some fine likkers.

Thanks, glad to get the validation of experience. Most of it's over my head, too. That's why it's "research and theory", right?

(or just GC, FTM)

FTM? Wikipedia turned up "Female-to-male transsexual; see transman."... I'm guessing you're talking about something else?

I know how to use an NMR, where to rent time, and they're kinda fun. I'm guessing the resolution will be crummy, but how do I find someone with a spare GC-MS? Is commercial testing outrageously expensive?

[helmingstay]

Ok, after a little more research and consultation with professor, it looks like the standard methods include:

GC/FID (gas chromatography / flame ionization detection )
http://www.sae.org/technical/papers/930377

FTIR ( fourier transform infrared spectroscopy)
http://www.sciencedirect.com/science?_o ... 236009592b

For anyone considering professional micro-production, the second paper looks especially informative.
From Food Chemistry Volume 101, Issue 2, 2007, Pages 825-832,
"Rapid quality control of spirit drinks and beer using multivariate data analysis of Fourier transform infrared spectra":

"The results obtained suggest that FTIR is a useful tool in the quality control of alcoholic beverages, since quantitative determination of essential compounds as well as chemometric classification are simultaneously possible. Through use of FTIR screening, the majority of all samples were classified as being in conformance with legal and quality requirements. Only conspicuous analysis results (approx. 12% of all samples), which exceeded the predefined limits, must be confirmed by complex and labour-intensive reference analyses. In comparison to conventional methods, FTIR spectroscopy is faster and only requires a simple sample preparation.

[wineo]

Isnt methanol just wood alchaol.The more woody the fruit,or seeds=more methanol in your booze.I always throw out the first pint,and dont worry about it,but the seeds will give off some bad flavors,and tannins,so watch out for them.Small seeds are ok,but cherry pits,peach pits,seeds in apples,citris etc are bad.Keep them out of your fermenter,unless you want some bitter booze.
wineo

[helmingstay]

Isnt methanol just wood alchaol.The more woody the fruit,or seeds=more methanol in your booze.
wineo

Not really. "Wood alcohol" traditionally refers to a method of producing pure methanol from wood via bacterial fermentation or chemical degredation. We shouldn't _ever_ see this without bad bacterial contamination or with yeast friendly temperature and pH. In short, woody materials like grain husks, etc don't produce methanol in a homebrew mash.

Separately, methanol can be produced by fermenting pectin-containing fruits. Some fruits have more pectin than others, and many fruits, i.e. apples, contain the most pectin in and around their seeds (ask grandma how to make raspberry jam - you boil apple cores!). Potatoes, pears, and sugar-beets aren't really woody, but they contain a surprising amount of pectin and, in volume, can produce alot of methanol that needs to get cut out.

I'll keep everyone's advice about the smell and taste of cuts in mind. As near as i can tell, the methanol cuts smell really good, light and fruity. I guess i need more experience.

[goose eye]

helmingstay how you makein your cider. you squezein your apples for
jucie or is you mashin an chunkin em in a barel. or do it mater

[The Chemist]

FTM? Wikipedia turned up "Female-to-male transsexual; see transman."... I'm guessing you're talking about something else?

Great day in the middle of the night!!! I only meant "For That Matter"!!! LOL

I know how to use an NMR, where to rent time, and they're kinda fun. I'm guessing the resolution will be crummy, but how do I find someone with a spare GC-MS? Is commercial testing outrageously expensive?

Wherever the is NMR, there is likely to be GC/MS nearby...

I've always found FTIR to be a pain in the ass (PITA? or is that some other weird thingy?) GC/FID is good, but you have more work to do to identify the peak of interest. MS just tells you right off the bat!! If you're not too scared that I'm "The Man", I would run a sample or two...

[helmingstay]

helmingstay how you makein your cider. you squezein your apples for
jucie or is you mashin an chunkin em in a barel. or do it mater

Food processor - all the solids are going in da barrel.

[helmingstay]

I've always found FTIR to be a pain in the ass (PITA? or is that some other weird thingy?)

I suffer from a hopeless un-understanding of the time domain, while the frequency domain has always treated me well. No first-hand experience with FTIR... the abstract sounded rather promising!

GC/FID is good, but you have more work to do to identify the peak of interest.

I figured you'd run standards in parallel and match time-to-elution... but then again, i've never used one.

MS just tells you right off the bat!! If you're not too scared that I'm "The Man", I would run a sample or two...

Sounds like a plan. Sample prep? I've borrowed them from a friend anyway, and i'm sure he/she would send something extra

[The Chemist]

All I'd need is 1 ml of a wash with pectinase and one without with one ml vodka added to each (preservative).

[schnell]

NMR or FTIR of a complex mixture will give you a useless spectra that will be very difficult to analyze.

that's why chromatography is such an important first step for many analytical methods. seperate, then measure, seperate, then measure.

and don't inject water into anyone else's GC either. they'll be mad.

you'll want either headspace analysis or purge and trap to feed any type of gas chromatograph to measure volatiles like methanol.

(since you're in new mexico i could point you to a lab locally... drop a PM)