Hexane use in wine

"Dee Randall" wrote .........

What a heavy subject on a sunny Sunday afternoon!!!!!

Dee, this would appear to be right down Professor Lipton's alley.

However, my understanding is that Hexane is not present in wine.

It *MAY* be used in laboratory testing of material, including wines, corks, barrels etc to determine the presence of polychlorides; residues of fungicides, insecticides or other volatile compounds where the hexane is used as an extraction agent.

HTH

st.helier

Dee, Hexane is a component of gasoline, among other things. It has a very pungent odor that some find quite unpleasant. I would doubt if there were much, if any, present in wine. Can you give me some context for your concerns? Is there an article you can steer me to?

Mark Lipton

I am wondering since some grapeseed oil is made by expeller method and some using hexane, whether grapes to make wine are exposed to hexane (yes, :-)) I know (or at least I think I do) that the grape stomper is not trying to get oil out for his wine.

I 'think' I understand that hexane is or can be used to see how much pesticides etc. are in a product, but that is not of which I am speaking.

So, I guess my very basic question is: is hexane used in the 'production' of wine?

Thanks for your reply. Dee Dee

I do not think it would be very cost effective to add hexane to wine or grapes to extract grapeseed oil. One would first save the must for making wine, after pressing. The solid residue after pressing containing the grapeseed, skins, stems and other solids then could be heavily pressed or ground to break up the grape seed. Since hexane is a good solvent for oils and not a good solvent for water, extracting the residue with hexane would extract much of the grapeseed oil into the hexane which would float on top of the solid residue and any residual water in it. Thus the hexane layer containing the grapeseed oil could be removed easily. Taking one isomer, n-hexane as an example, this has a boiling point of only 69 degrees compared with 100 degrees for water. Grapeseed oil would have a very high boiling point. Thus the hexane could be recovered from the grapeseed oil by distillation and reused. If one wants to change the taste of the grapeseed oil as little as possible, one could use vacuum distillation to lower the boiling point even more.

I doubt if many, or any, wineries would also extract grapeseed oil. Likely a special plant for extraction of grapeseed oil would use the solid residue of many wineries to be cost effective.

Since pure hexane is expensive, many extraction processes would use "petroleum ether" which is a low boiling point hydrocarbon mixture that would contain various isomers of hexane and some slightly lower and higher molecular weight hydrocarbons. It is obtained by fractional distillation of petroleum.

The LD50 of n-hexane taken orally for young adult rats is about 49 ml/ kg of body weight.(Kimura). That for humans might be somewhat below or above this. The LD50 is the dose that kills the rats 50% of the time. A 100 kg human is not unusual. That means that it would take 4900 ml of hexane to kill 50% of 1 kg humans given this amount. Since hexane is so very slightly soluble in water, it likely would take many L of water or wine to contain enough dissolved hexane to even cause mild symptons in humans - more than even the most hopeless alcoholic can drink. If one added more hexane to the water or wine than will dissolve in it, the excess hexane would float on top of the wine, it would not smell or taste anything like water or wine, and anyone could tell something is wrong.

Since hexane and pure alcohols mix well, one might be able to dissolve enough hexane in say 80% alcohol(160 US proof) rum to be of health concern. However the taste and smell would be so foul that I doubt if anyone would drink such a mess.

That would be 50% of the 100 kg humans, but I bet you knew that. Not to be argumentative, this is just for the benefit of the metrically challenged readers. :)

Oops! Yes there is a typo. It should be a 100 kg human. Even a live 1 kg premature baby likely is very rare, if there are any live ones of this weight at all :-) .

You say, I do not think it would be very cost effective to add hexane to wine or grapes to extract grapeseed oil.

However, Berio does say in an email to me that "Grapeseed oil is solvent-extracted."

Thanks for the long reply. Dee Dee

Dee, The production of grapeseed oil has little to do with the production of wine. The grapeseeds are part of the pomace, the solids that are left after the pressing. That's what would be, I suppose, extracted with hexane, though I doubt that any grapeseed oil destined for food would be obtained by hexane extraction. FWIW, though, after the extraction, the hexane will be evaporated, leaving next to none in the oil.

Mark Lipton

After reading several sites concerning grapeseed oil, I find that those wanting to sell you a high end product make a point of the fact that they produce the oil only by pressing and not solvent extraction. They elude to the possibility that some solvent extraction methods might leave a slight residual taste, and seem to play on much of the public's fear of the word "chemical" in reference to food. Just how many oil producers use only pressing and how many use solvent extraction is unclear. Grape seeds contain much less oil than many seeds or pulps used for many more popular oils, such as olive oil. The grape seeds have to be well crushed to extract the oil in a reasonable time using solvent extraction or very heavily pressed to obtain much oil by pressing alone. Some who only press go to considerable trouble to separate the grape seeds from other solids such as skins, stems, etc before heavily pressing them for oil.

The main selling point for grapeseed oil seems to be that it can be used to saute at very high temperatures without burning, unlike many popular fats such as butter. Some make a fuss about the distribution of "good" and "bad" fats in various oils. However grapeseed oil tends to be rather bland in taste, so it can not compare with even a medium quality olive oil when a good taste is desired. Of course there are those who want an oil to have as little taste as possible.

Anyway, at least for grapes that can produce decent wine, the wine comes first and the grape seeds left after pressing the grapes for wine are mainly a low value byproduct.

When I emailed Filippo Berio, a very large oil producer regarding a specific grapeseed oil they produced and I bought: "As it does not say "expeller" pressed" on the bottle, can you tell me if this product is chemically extracted."

The email answer to me from Berio was quote, "Grapeseed oil is solvent-extracted."

So, it must be some chemical, so I was wondering if it were 'hexane' used to extract; and, then, of course, if any were left as residue. OTOH, I would be wondering the same no matter what chemical were used.

Thanks for your response. Dee Dee