Can ethanol emulsify olive oil?
Bill Velek
can help me because I know practically nothing at all about chemistry.
My hobby is homebrewing, and recently there have been some discussions
about the possibility of using a tiny amount of olive oil in a
fermentation to help promote yeast growth. Apparently the New Belgium
Brewery successfully experimented with the use of olive oil on a
commercial scale, but scaling it down to the typical 5-gallon size of
most homebrewers requires a tiny fraction of a drop of oil which is
beyond the means of homebrewers to measure. Using too much oil is
likely to ruin head-retention (foam). Someone suggested adding a drop
to a measured amount of ethanol, which is supposed to emulsify the oil
and then a measurable amount of the ethanol/oil mix could be measured
and added to the brew. In other words, the theory is that if I need
one-hundredth of a drop of oil, I could add one drop to 99 drops of
ethanol, mix it, and then take one drop of the resulting solution.
Would that work? I could buy a test-tube and try it, but I'm not sure
I'd be able to see whether the olive oil is still floating on the
surface or whether it has mixed (dissolved?). Any help will be
appreciated. Thanks.
Bill Velek
Bill Penrose
> ... Someone suggested adding a drop
> to a measured amount of ethanol, which is supposed to emulsify the oil
> and then a measurable amount of the ethanol/oil mix could be measured
> and added to the brew.
I'm not sure olive oil is soluble in ethanol. If you use an emulsion,
a lot of oil will stick to any glass surfaces or droppers you use.
A thought: You might try soaking a drop of olive oil into a sheet of
sterilized paper towel, measuring the size of the stain, and taking
about 1/100th of that and dropping it into the vat.
Leaving the oil on the paper for awhile will give the oil time to
become evenly distributed. Sterilize the paper first if you can.
Dangerous Bill
Bill Velek
snip
> Olive oil should certainly be soluble in ethanol at 1%. Your proposed
> method is logically fine.
>
> One way to explore a bit is to exaggerate... Try making a solution at
> 5% (5 drops oil + 95 drops alcohol) and see what it looks like. It
> will be better at 1%, but harder to see.
>
> A caution... The effect of the olive oil on your product may not scale
> simply. The olive oil is probably doing more than one thing -- as you
> note when you mention foam. So try it and see what happens; you may
> want to experiment with how much you add.
>
> bob
Thank you VERY much, Bob, (and Bill Penrose, next post) for taking the
time to reply ... and so quickly. Yes, I will need to experiment a bit
with this. Since it's been done on a commercial level already, it will
probably be pretty safe so long as I can limit quantity proportionately
to what the New Belgium Brewery did. As explained, that will require a
diluted solution as I described, or perhaps using the procedure that
Bill Penrose outlined, which sounds a bit more difficult but is a good
alternative idea. Bill mentioned his idea because oil might stick to
the glass when I attempt to dilute it, but if that can be resolved, I
think it would be infinitely easier for me to count drops to know the
dilution level as opposed to trying to measure and divide surface area.
However, if he is correct about oil sticking to the glass, his
procedure might be the only practical way to do it. So, my follow-up
question is this: if I do add one drop of olive oil to 99 drops of
ethanol, while it might want to cling to the glass initially, will
sufficient shaking of the vial break or dissolve the oil away from the
glass and emulsify it? And by the way, I can work with larger
quantities such as 10 drops of oil and 990 drops of ethanol if the
larger amount will shake up better and decrease the amount of oil that
might stick to the glass.
Also, which would be better -- relatively pure ethanol or vodka? I
don't know if a bit of water would help or hurt. Everclear is 97.5%
ethanol and 2.5% water; 100-proof vodka is 50% ethanol and 50% water.
Thanks in advance for any follow up advice. If you're ever in central
Arkansas, I'll have to treat you to some of my homebrews. :-)
By the way, if you're curious about why olive oil might be added to
fermenting beer, it is to eliminate the need to aerate the wort, which
is a bit difficult to do very well. Here is a brief excerpt from the
explanation from New Belgium:
> "The basic concept is that since yeast uses an oxygen atom to pull a
> hydrogen away from an 18 carbon chain unsaturated fatty acid to make a
> monounsaturated fatty acid chain to help it grow, you could simply
> provide an 18 carbon monounsaturated fatty acid and it would be able
> to use that. This works well in practice, we made a little over
> 1 million bottles with beer where the yeast had had olive oil added.
Thanks again.
Bill Velek
Bill Velek
snip
> A thought: You might try soaking a drop of olive oil into a sheet of
> sterilized paper towel, measuring the size of the stain, and taking
> about 1/100th of that and dropping it into the vat.
>
> Leaving the oil on the paper for awhile will give the oil time to
> become evenly distributed. Sterilize the paper first if you can.
Bill, that would be more difficult to do, but if the other method
doesn't work, you have provided what sounds like an excellent
alternative. Also, please see my follow-up post in this thread that I
just posted in reply to 'Bob'.
Thank you VERY much for your time.
Bill Velek