olive oil "aeration"

DrPaulsen · Post by **DrPaulsen** » Wed May 04, 2011 12:12 am

I tried out the fabled olive oil "aeration" trick on an English Brown Ale and American IPA I brewed on Good Friday. (These were extract kit beers from the AHS 20th anniversary series.) So far I am very impressed. Both beers had short lag times (6-7 hrs), exhibited vigorous fermentations, and attenuated appropriately. The English Brown Ale used WLP005 (1L, 1.040 starter, shaken occasionally) and attenuated 75%, while the American IPA used Wyeast 1056 (1L, 1.040 starter, stir plate) and attenuated 90%. Note that the IPA attenuation was driven up by the pound of turbinado sugar I added to dry out the beer a bit.

The beers look and taste great so far and I am sufficiently impressed to start doing this from now on. I simply added a single drop of olive oil from a piece of stainless wire to the fermenter and then stirred it up a bit. According to some folks that was way too much olive oil, but it was the smallest amount I could reasonably "measure".

It would be interesting in the future to do a split batch and check an olive oil beer vs an O2 beer side-by-side, but that will have to wait until I have more time.

Post by **JimPotts** » Wed May 04, 2011 9:58 am

What volume of olive oil would have been ideal? Is there an "x mg per y billion cells" type goal?
-Jim

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DrPaulsen · Post by **DrPaulsen** » Wed May 04, 2011 10:46 am

http://brewcrazy.com/hull-olive-oil-thesis.pdf

This research used something in the range of 1 mg of olive oil per 50 Billion yeast cells pitched. Since I probably pitched around 200 Billion yeast cells, that would mean 4 mg of olive oil. I have not bothered to weigh out 1 drop of olive oil, but I would imagine it's more than 4 mg.

hoboscratch · Post by **hoboscratch** » Thu May 05, 2011 7:57 am

I looked into doing this last year at some point. I never did try it, I'm glad you volunteered to be the guinea pig. Also glad that it worked for you. I do remember during all my reading about it that the amount of olive oil needed was ridiculously low, and extremely difficult to measure out for 5 gallons. So while you did probably put in more, I don't think there is a much better option other than what you did, dripping it off a piece of wire. That was what I had planned to do when I was thinking about doing this. What sort of aeration method did you use before? Shaking, or pumping O2? How would you say the lag time and attenuation compared to your old method?

DrPaulsen · Post by **DrPaulsen** » Thu May 05, 2011 8:08 am

Previously I've used hardware-store-O2 with a 0.5 um diffusion stone.

My typical lag times have been 12-18 hrs for ales and 24+ hrs for lagers. (For the sake of simplicity, I measure lag time from when I pitch to when I first see CO2 bubbles indicative of active fermentation.) To see a 6 hr lag really surprised me, especially given that I pitched and fermented at 64F.

In the future, I'd like to do a split batch, where I use O2 on one fermenter and olive oil on the other, with a common stir-plate yeast starter used for both (i.e. make a single 3L starter with 2 packs of yeast and do my best to evenly split the slurry between fermenters).

hoboscratch · Post by **hoboscratch** » Thu May 05, 2011 8:23 am

Yeah, I've never gotten lag times like that. Its impressive. I use a bucket to ferment in so I'm not 100% sure of my lag time in terms of just seeing when co2 bubbles start to form, but my airlock is usually bubbling within 24 hours.

Post by **JimPotts** » Thu May 05, 2011 9:31 am

I think splitting a large batch into three would be a good comparison. One with oxygen, one with oil, and one without extra aeration. Then you could really compare ester profiles, etc.

-Jim

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brownbeard · Post by **brownbeard** » Thu May 05, 2011 10:09 am

I rarely wait 12 hours for fermentation to begin. I use an aquarium pump for aeration. I always use yeast nutrient.

I may try this olive oil treatment.

Matt F · Post by **Matt F** » Thu May 05, 2011 12:59 pm

Very cool. I am curious to see some of your side-by-side experiments. I use the same 02 setup as Lee with a stone and welding tank. Works great. I used Larry's aquarium pump in the past and it worked great. My lag time has been really short with either of the two oxygen systems. Seems to be most dependent on the activity of my yeast starter. I often pitch the starter while it is very active and have had bubbles in less than 3 hours on a few occasions. 12 or less is most typical for me.

hoboscratch · Post by **hoboscratch** » Thu May 05, 2011 1:08 pm

Just to clarify, you guys are talking bubbles on the surface, not a bubbling airlock, correct?

Matt F · Post by **Matt F** » Thu May 05, 2011 1:39 pm

Yeeeaaaahhh!

DrPaulsen · Post by **DrPaulsen** » Thu May 05, 2011 2:46 pm

hoboscratch wrote:Just to clarify, you guys are talking bubbles on the surface, not a bubbling airlock, correct?

I count the lag phase over from the first formation of a thin, coherent layer of bubbles. This typically correspond to the beginning of regular airlock activity.

Matt F · Post by **Matt F** » Thu May 05, 2011 2:51 pm

Agreed, they start about the same time for me.

hoboscratch · Post by **hoboscratch** » Thu May 05, 2011 3:17 pm

Right on. I don't think I've done but one or two primaries in a carboy so I didn't really remember the timing.

hoboscratch · Post by **hoboscratch** » Fri May 06, 2011 9:21 am

Brewing an IPA right now, going to try the olive oil.