Olive oil for yeast health - Experimentation

[black_labb]

Some people would have seen some talk or descriptions on using olive oil to yeast instead of oxygen. The idea is that yeast metabolises oxygen to produce unsaturated fatty acids and sterols which are required for yeast health and budding (multiplying). Instead of giving it oxygen, you add some olive oil to provide the unsaturated fatty acids.

An experiment and thesis was done by the brewer at New Belgium Brewery in America where they replaced Oxygen with a small amount of olive oil and see what happened to the final beer. Basically the beer fermented well and took a bit more time to finish fermenting and had a bit more esters. The resulting beer also was more stable as it had less contact with oxygen which causes oxidation and staling.

http://brewcrazy.com/brewing-beer-with-olive-oil-article/

What bothers me about the thesis is they seem to ignore the sterols the yeast requires for health and focus on the unsaturated fatty acid. I'm not sure how difficult it is to add sterols but the experiment seems unfinished if you don't even try and do something out about testing to see what the olive oil and sterols do together, which is where my much less professional experiment comes in. Olive oil and a source of sterols which I've been able to get into wort through the action of yeast metabolising oxygen. Basically I am testing normal brewing aeration vs normal brewing aeration with a bit of olive oil. Shaking and pouring wort is not really adequate for proper yeast health and many people purchase oxygenation kits and similar to inject o2 into their wort at pitching time. I'm cheap and try and do similar by thrashing the wort 12-24 hours after pitching to add o2 to the wort after the yeast has absorbed the inital hit of o2. This is a common english technique, particularly using yorkshire squares (though they use a pump usually)

I read some people saying it seems difficult to implement tbe use of olive oil to home brewers but it seems simple to me. The most difficult thing is to measure out the amount of olive oil, which is something like 0.008g for a 20ish litre batch. Someone approximated it to being the amount of olive oil that would stick to a dipped pinhead. I decided that the tip of a steak knife just touching the olive oil and then put into boiling wort or water (for sterilisation) would be good enough.


So far I've brewed a batch of an English bitter in 2x10L cubes. I was going to pitch one cube to each different fermenter but I decided to pour the cubes roughly equally into the fermenters.

The procedure is as below

1. Boil and cool leftover wort from settled trub and a bit of sparging in kettle for yeast starter (approximately 1.5L, this is my usual yeast preparation)

2. Add swollen wyeast pack to cooled wort which is still in the pot and swirl to mix. Yeast chosen was wyeast 1187 ringwood ale, a yeast I know well.

3. Dip tip of steak knife in olive oil and rinse in 100ml boiling water

4. boil water with slight bit of oil for 10 minutes (used microwave)

5. add oiled water to one fermenter

6. splash wort/yeast from pot into 2 fermenters. I would give one splash to one, then the other repeated as evenly as I could.

7. After about 6 hours I added 12ish litres of wort from one cube evenly (see above for method)

8. After another 12 hours another 9ish litres from the second cube splashed evenly between the fermenters. This was done as I was seeing evidence of fermentation in both fermenters (Kitten fur was seen on top of the wort, suggesting that the kitten had found it's way in). There was no noticeable difference in activity levels of the kitten.


So now I have the 2 fermenting side by side in as similar conditions and teatment as possible (other than the olive oil). They are sitting under the house where I normally ferment. Right now it is sitting between 16.5 and 17* there which works well for ringwood as a start temp ( I will ramp the temp up over fermentation)

Currently at 24ish hours after the second wort addition I've done a gravity sample.

The OG was 1046

The olive oil sample was reading 1035
The aeration only sample was reading 1037

There was little noticeable difference in the amount of krausen and the fermentations both seemed healthy.

I'll keep updates going as it goes. This could be a possible method to improve yeast health without mucking about too much with oxygen bottles, aeration pumps or thrashing the wort.

 

[tiprya]

This gets brought up every 6 months or so (there are a few threads already), but I'll be very interested in the results of your experiment.

 

[black_labb]

This gets brought up every 6 months or so (there are a few threads already), but I'll be very interested in the results of your experiment.

I agree, I've seen it enough times but never really observed much action. I thought a side by side experiment would be worth a bit of my time on my day off (that I should be spent doing that report). For me the addition of olive oil to wort for my usual yeast management would literally take less than 30 seconds - dipping a steakknife into my yeast starter wort while it's boiling and then rinsing the knife and drying it. If it improves the yeast health it could be a very productive use of 30 seconds.

 

[MHB]

The original "Hull Olive Oil Thesis" published in 2005, just short of a decade ago still makes interesting reading. As mentioned above it keeps reappearing here or on other fora, usually by people who want to avoid the expense of aerating properly.

The question I always have is if it was really effective would commercial brewers be doing it? the answer being yes they would and no they aren't.

Personally I am less than impressed with the idea of aerating part way through the ferment; causing yeast to switch back and forth between reproductive aerobic state and the anaerobic alcohol producing state will reduce the yeasts stores of glycogen, lipids, sterols and fatty acids. Boosting these (well some of them) are exactly why the Olive Oil thesis was invented, intermittent aeration looks like a good way to undo any potential benefit.

When it comes to yeast, there is a lot of difference between healthy and happy yeast and a lot of yeast - and the beer they make. I strongly recommend you read the original thesis, there is a fair bit in there that doesn't appear in the popular science version linked to above.
Mark

View attachment hull-olive-oil-thesis.pdf

 

[Yob]

As I understand it, should be ok if you are using the yeast once only, it doesnt provide much for the yeast to repair after budding though so overall not great for yeast health. (particularly if you ranch)

Very interested in your results too Dr Labb

 

[Feldon]

Just wondering whether boiling the water to which you have added the olive oil would possibly denature the unsaturated fatty acids, and particularly so if you are using microwave energy to boil the water/oil mixture.

 

[black_labb]

The original "Hull Olive Oil Thesis" published in 2005, just short of a decade ago still makes interesting reading. As mentioned above it keeps reappearing here or on other fora, usually by people who want to avoid the expense of aerating properly.

The question I always have is if it was really effective would commercial brewers be doing it? the answer being yes they would and no they aren't.

Personally I am less than impressed with the idea of aerating part way through the ferment; causing yeast to switch back and forth between reproductive aerobic state and the anaerobic alcohol producing state will reduce the yeasts stores of glycogen, lipids, sterols and fatty acids. Boosting these (well some of them) are exactly why the Olive Oil thesis was invented, intermittent aeration looks like a good way to undo any potential benefit.

When it comes to yeast, there is a lot of difference between healthy and happy yeast and a lot of yeast - and the beer they make. I strongly recommend you read the original thesis, there is a fair bit in there that doesn't appear in the popular science version linked to above.
Mark

hull-olive-oil-thesis.pdf

I went through that the other day, the link above was specifically for people to get a basic understanding but it has a link within it to the thesis as well.

If the unsaturated fatty acid is infact a good partial substitute then I wonder if the sterol could also be added directly as well. If this was found to be effective then there could be a product like yeast nutrients developed that specifically provides the sterol and unsaturated fatty acids. That's assuming there is a reasonable source of sterol that can be produced/cultivated. Back to your point, if this was in fact functional then I'm sure someone would have tried to produce such a nutrient, I can imagine a product like that would be quite profitable once it caught on to a few major breweries. I'm sure I'm not the first one to join the dots and you are probably right that it isn't a magic cure.

In my eyes homebrewing aeration is often a bit borderline on acceptability. When we met you had just brought out the oxygen kit and you were telling me how you think it is the most common issue holding back some homebrewers. I'm trying to avoid adding equipment to my brewing setup as I'll probably have less space for brewing and equipment in the future and I want to see what I can economise on.

A full effectiveness test would involve a third example that was aerated/oxygenated using a method that produces ideal conditions reliably. If the results of this test show any worthwhile difference it may be worth going further (with the help of someone else with the right equipment ideally).

As I understand it, should be ok if you are using the yeast once only, it doesnt provide much for the yeast to repair after budding though so overall not great for yeast health. (particularly if you ranch)

Very interested in your results too Dr Labb

I'm planning on reusing both yeasts to see what happens on the next batch. I haven't decided whether to add more olive oil yet and what to do next. I'm tempted to do a 10L (2x5L) batch of barley wine to really find out how the yeast in the 2 cases has held up with 2 generations growth with olive oil.

 

[black_labb]

Just wondering whether boiling the water to which you have added the olive oil would possibly denature the unsaturated fatty acids, and particularly so if you are using microwave energy to boil the water/oil mixture.

I would suspect it wouldn't. I know that olive oil does break down at high temperature frying but that is much higher than 100*c.

I doubt that microwaves cause any significant change to the structure in any quantity that would interrupt the experiment (even if 90% of the molecules changed somehow it would be fine for my experiment, the tip of a steakknife is far from accurate measurement and probably quite a bit more than required for an effective experiment)

 

[technobabble66]

Another minor little detail is the amount of Olive oil that ends up on the sides of your container rather than in the wort, after all the faffing around. It'd be fairly safe to say the OO will be sterile for the purposes used here, so the boiling thing should not be needed (NB: IMO).

I add OO to my brews also, after beating the crap out of them to aerate. So long as i don't screw up the temp control i've had great fermentations going, but obviously no side-by-side comparison to really tell. FWIW, The amount i add is by dipping the tip (0.5-1cm) of a (sterilised) steel skewer into some OO, knock any drops off, swish the skewer through the wort, then beat the hell out of the wort for a bit longer.

V keen to see your results!

 

[MHB]

[SIZE=medium]The idea of a combined nutrient that contains everything to keep yeast healthy and happy has been proposed before, about as often at this idea gets posted.[/SIZE]
[SIZE=medium]Truth is it’s already been done, often and by many brewers. If you want the perfect environment to propagate and perpetuate yeast, it’s called a wort.[/SIZE]
[SIZE=medium]Just add the recommended amount of nutrient to insure that there is enough trace elements, vitamins, minerals and nitrogen available – aerate well and away you go.[/SIZE]
[SIZE=medium]Mark[/SIZE]

 

[black_labb]

The nutrient comment was aimed as a nutrient to replace oxygen, not all the required minerals. Specifically Sterol and unsaturated fatty acids. Unless sterol wasn't available in a suitable form I'm sure it would have been done by now if it worked.

 

[black_labb]

I'm thinking for the next generation of yeast I'll brew a Baltic porter. It's a style I've wanted to do for a while and I'm much more likely to get through it than a barley wine. The 1187 is probably too estery for a baltic porter but I'll do my best to get a clean ferment by keeping temps low and any issues with the yeast will increase esters pulling it out of style.

I can manage about 32L of around 1080-1090 mashing twice (my mash tun/malt pipe is my limiting factor at 19L). I'll add another "tip of the knife" dose to the olive oiled brew and leave the other as is.

Treating the first split batch as 2x 10L simple starters I would be overpitching by about 50% if I went straight onto the yeast cake assuming 2x16L of 1085. To me this sounds reasonable considering it was a fully fermented beer (yeast not as viable as a starter) and that I'm planning on keeping the fermentation temp around 15-16 for a long while into the ferment. If anyone has other thoughts on this I'm interested in your opinions.

I'm planning to be pitching onto the yeastcake and then racking into a second fermenter around 12-36 hours later to get the ferment off dead cells and trub that would have settled out by then. I may rinse the yeast instead but racking it off early seems like a good method to keep it off all the trub not just the trub from the previous brew. The bitter shouldn't be too detrimental to the yeast and ringwood won't need to be crash chilled for long for clarity.

 

[black_labb]

By the way I did a gravity sample and the olive oil sample is 1022 with the aeration 1024. The olive oil still has a 2 point lead but both are going well. FYI I put a heat belt around the 2 fermeters after the gravity sample yesterday to ramp the temp up.

 

[peas_and_corn]

Here's the thing. Commercial breweries spend a lot of money to get the dissolved oxygen content of the finished beer down to 10ppb. Given that, if this worked commercial breweries would be using this technique- but there are no breweries that do.

 

[Spohaw]

Still new to brewing but I thought any oil in the fermenter would affect the head quality of the beer

Cheers Spohaw

 

[black_labb]

Here's the thing. Commercial breweries spend a lot of money to get the dissolved oxygen content of the finished beer down to 10ppb. Given that, if this worked commercial breweries would be using this technique- but there are no breweries that do.

Absolutely, commercial breweries put much expense into the oxygen level up to 10ppb. Homebrewers by large don't put much effort or expense into oxygen but many brewers report improved fermentation/yeast health when they do. This experiment isn't trying to revisit the concept of "complete replacement" of oxygen but simply to see if a bit of olive oil could improve yeast health in a wort where oxygen levels are acceptable on a homebrew level but not ideal.

I'm not suggesting that there is going to be a revolution around the way people brew, but I'd like to see if it improves yeast health in my beers. I personally feel that there is more I could do for yeast health; in particular my bigger beers.

Still new to brewing but I thought any oil in the fermenter would affect the head quality of the beer

Cheers Spohaw

If you read the thesis linked above there was no difference in head quality. There is probably more oil from hops in many beers than there is olive oil in this beer.

 

[peas_and_corn]

Absolutely, commercial breweries put much expense into the oxygen level up to 10ppb. Homebrewers by large don't put much effort or expense into oxygen but many brewers report improved fermentation/yeast health when they do. This experiment isn't trying to revisit the concept of "complete replacement" of oxygen but simply to see if a bit of olive oil could improve yeast health in a wort where oxygen levels are acceptable on a homebrew level but not ideal.

I'm not suggesting that there is going to be a revolution around the way people brew, but I'd like to see if it improves yeast health in my beers. I personally feel that there is more I could do for yeast health; in particular my bigger beers.


If you read the thesis linked above there was no difference in head quality. There is probably more oil from hops in many beers than there is olive oil in this beer.

I was referring to the finished product, hence the use of the word down. 10ppb oxygen is waaaay too low for wort.

 

[black_labb]

Currently both samples are sitting at 1017.

I was referring to the finished product, hence the use of the word down. 10ppb oxygen is waaaay too low for wort.

Sorry, was thinking 10ppm and made assumptions about what you were saying instead of reading correctly. It was a long day yesterday before meeting some brewers/beers.

 

[black_labb]

Update - Pretty sure both have reached FG. Yesterday the olive oil sample was sitting at 1013 and the aerated only sample was sitting at 1014. Today both are sitting at 1013.

On thing that I have noticed over the last 4 days is that the olive oil sample has been noticeably clearer, even while still clearly fermenting. Currently the aerated example is quite clear; as clear as I would expect from a beer with a flocculant yeast at FG. The olive oil example is as clear as I would want a finished beer, simply crystal clear, even yesterday when it only just got to FG.

I'm going to chill them both down to about 8-10* for a couple days starting tomorrow pm assuming FG is stable.

I brewed the Baltic porter for the second generation of the yeast. I've got about 32-34L in cubes that I expect is about 1080. I'll be pitching this directly on the yeast cake and transferring into a second fermenter after about 12 hours to get it off the trub and dead yeast cells.


Right now I'm feeling pretty happy with what results I'm getting. In some cases I've had beers that refused to clear up and wondered if it could possibly be yeast related. Having a slightly quicker ferment with the olive oil and fermented beer that seems clearer than I've ever had before seems worthwhile to me. It also suggests that aeration/yeast health could be an area for attention to focus on in my brewing; using olive oil or otherwise.

I'm really looking forward to the Baltic Porter. I lost a bottle of Lvivske Porter at an airport a year ago and the Zwiec porter I've had since doesn't quite do it for me. Hope at least one of the batches does, otherwise I'll have 30L+...

 

[black_labb]

Update for the last week. The Bitter has been bottled/flexicasked on thursday. I'll be able to test the Cask Examples In about a week and a few extra weeks for the bottled versions.

The Baltic Porter was pitched onto the yeast cake at 14* on thursday with another steakknife tip of olive oil with wort going onto the olive oiled yeast cake. I racked sloppily into a second vessel on friday afternoon to get a bit of extra aeration. It's been sitting in a fridge at 15-16* the whole time. I had the probe just in the fridge as it didn't reach to the fermenters so the ferment likely was warmer at it's peak, but I didn't measure it.

Currently they are both sitting at 1031 after 3 days and there is plenty of active yeast still in suspension. Hydrometer samples may have suggested slightly smoother flavour to the olive oiled wort but that could be due to carbonation differences or the fact that the non-olive oil sample is in a vessel that doesn't separate trub nearly as well as the other and I forgot to put the widget in behind the tap (to prevent trub/yeast being pulled through). I may rack again this evening before fermetation slows down too much for this reason. I don't want to have one age worse than the other because I've packaged it with trub and excess yeast.