Sciencemadness Discussion Board

Concentrating Home-made wine

Helix - 24-10-2008 at 14:06

Recently, I made some home-made wine with sugar, yeast, and water. I'm not really looking to drink the stuff, but I was wondering if I added Anhydrous Magnesium Sulfate(baked Epsom salt) into the wine to concentrate it. I would wait for the MgS04 to settle and then siphon off a good chunk of wine, leaving the Magnesium Sulfate at the bottom. Or if I had access to low flow filters, could I use those to filter off the Magnesium Sulfate?


Note: This is more of a hypothetical question than practical application.

JohnWW - 24-10-2008 at 14:14

MgSO4 is much too soluble in water, and indeed in water-ethanol mixtures, for that to work. Too much would remain in solution. Using it in conjunction with freezing the MgSO4 solution in wine would also not work, because together the MgSO4 and ethanol would considerably depress the freezing point. The best way, other than by distillation to make brandy or rum, and back-blending that to make a fortified liqueur, would be by freezing it as it is so as to precipitate some of the water as pure ice, although again the freezing-point would be significantly depressed. However, this would also concentrate the fusel oil - higher alcohols especially amyl alcohol - which are toxic in large amounts.

kclo4 - 24-10-2008 at 14:21

I think I have seen an example where Potassium Carbonate(I believe?) can cause Ethanol to salt out. This may work to concentrate the alcohol. It would require a lot of carbonate.

Helix - 24-10-2008 at 14:23

Quote:
Originally posted by JohnWW
MgSO4 is much too soluble in water, and indeed in water-ethanol mixtures, for that to work. Too much would remain in solution. Using it in conjunction with freezing the MgSO4 solution in wine would also not work, because together the MgSO4 and ethanol would considerably depress the freezing point. The best way, other than by distillation to make brandy or rum, and back-blending that to make a fortified liqueur, would be by freezing it as it is so as to precipitate some of the water as pure ice, although again the freezing-point would be significantly depressed. However, this would also concentrate the fusel oil - higher alcohols especially amyl alcohol - which are toxic in large amounts.


Thank you for the very quick response. What about using a centrifuge to try and pull the MgS04 out of solution?

And one semi-related question:

Does yeast produce fusel oils?

kclo4 - 24-10-2008 at 14:30

I think the yeast does. Especially when the tempurature, pH or levels of neutrients (specifically nitrogen) are off.

Sorry this is off-topic-ish but Is there a way to dramatically increase the amount of fusel alcohols to form? I think it would be quite useful to concentrate those. Ethanol is easy to get, but the ones like butanol, amyl alcohol and furfural seem useful.

not_important - 24-10-2008 at 18:36

Quote:
Originally posted by Helix
... What about using a centrifuge to try and pull the MgS04 out of solution?

And one semi-related question:

Does yeast produce fusel oils?


Not any centrifuge that can be built here. Ionic salts in solution are not going to come out of solution from that sort of treatment.

You could use insoluble desiccants, such as zeolites. Distillation or very slow freezing out of the water are alternatives. Selective permeability membranes will let the ethanol through while holding back the water and sugars.

Yes, fusel oil (higher alcohols) is formed by yeast. Some breeds of yeast produce more than others, but usually other organisms are used to produce those alcohols by fermentation.