Olive Oil In Starter

[JonnyAnchovy]

What's the point, again?

Why not just stick to tried and proven traditional methods of aeration.

Proponents of oil are also claiming increased shelf life for beers. I'll be giving it a go for sure.

 

[hazard]

I brewed up an irish red ale yesterday (Saturday), pitched with oily yeast and no aeration, and going gang busters today!! Here are details.

My irish ale is a partial recipe with 3kg grain and 1 kg of light DME (will post on recipe DB). I finished with 24 litre of wort at 1050. After the boil was finished and wort cooled down, I carefuilly racked to to the fermentor to avoid splashing as much as possible.

I have been growing the starter this week as described earlier in this thread. I put the starter in the fridge on Friday night. Took it out of fridge on Sat morning, decanted top liquid and added 2 drops of oil. After warming up to room temp, the yeast was pitched at lunchtime Saturday.

First bubble popped through the airlock at 5pm Saturday afternoon, and by midnight was bubbling merrily. This morning, its bubbling 1 per second (or so).

So - at this stage, olive oil aeration is working well. I've got a strong fermentation going, and it started quicker than some of my brews which I did aerate. The ultimate test will of course be in the tasting of the final product and I will provide an update at some time. But for me - I have read about a lot of different ways to aerate wort, and this is surely the easiest way by far. And if it does increase shelf life through reduced oxidation then even better!

Hazard

 

[Sammus]

A fish tank aerator with a viral filter seems pretty basic equipment. Room air has sufficient oxygen content. Also, a venturi system (again with the filter) is quite easy to construct.

No need to use pure oxygen, studies have shown this has no advantage.

Oil up, if you wish, but be sure you have done the mathematics.

WJ

Really? Which studies show that? Because the guys at Wyeast labs did a presentation (you can get a copy of it here) in which they showed the methods and results of a lot of oxygenation techniques. They even clearly state that an aquarium pump through an air stone gives nowhere near sufficient oxygen levels (tops out at 8ppm, where as for most beers you probably want closer to 4x that).

I'd like to read the studies you're referring to, do you have a link or journal name/number/page?

 

[MHB]

For those that like to read - The Hull ThesisView attachment 26165

The idea of avoiding wort aeration has been getting played with for well over a decade. There are a couple of fundamental points that you have to be aware of: -

This is not a Yeast Propagation Method; it has to do with the health of the membrane in the cell walls of stored yeast. The assumption being that the pitch is of sufficient size not to require further yeast reproduction in the wort. From this it follows that this is not a method you would employ to build up a starter
As the study clearly indicates in the "Suggestions for Future Work" Olive Oil only supplies oleic acid, a vital part of the process; however far from a complete answer to yeast growth and health.

Personally I have no objections to the process and am looking forward to future results of the research, ultimately it could lead to some very smart yeast propagation and storage methods, but at this time it's far from a complete answer.



MHB

If you want to measure out small quantities of oil, I took a small dropping pipette and counted out 10 drops 3 times the average weight of water was 0.27g or 270 mg so 1 drop was about 27mg (of water) Olive Oil has a density of about 0.9.

So Hazard, you are looking for about 1/3 of a drop in your built up starter.
M

 

[hazard]

I brewed up an irish red ale yesterday (Saturday), pitched with oily yeast and no aeration, and going gang busters today!! Here are details.

I have now bottled the "olive oil" beer. FG got down to 1013, as planned, after 2 weeks and I chilled for another week before bottling last weekend. So, oil (or to be more precise lack of aeration) did not hinder fermentation at all. Will leave in the bottle for another week or 2 before I try it.

hazard

 

[muckanic]

Because the guys at Wyeast labs did a presentation (you can get a copy of it here) in which they showed the methods and results of a lot of oxygenation techniques. They even clearly state that an aquarium pump through an air stone gives nowhere near sufficient oxygen levels (tops out at 8ppm, where as for most beers you probably want closer to 4x that).

The context of this idea seems to get lost in the repetition. Sure, a one-off application of an air pump can't saturate a brew adequately with O2. However, who said the pump has to be turned off once the dissolved O2 levels plateau? Plus, it is debatable whether a fancy viral filter is necessary. I believe that solo yeast cells don't really float around in practice. A dust and possibly spore filter could be enough.

Thinking laterally, why not just use a pump on the starter rather than the main batch? It is presumably no less effective than a stirplate.

 

[Sammus]

Thinking laterally, why not just use a pump on the starter rather than the main batch? It is presumably no less effective than a stirplate.

Interesting point, though I know for sure that my air stone provides nowhere near enough agitation to keep the yeast in suspension - which I believe is one of the main points of a stirrer, along with driving out excess co2 and constant airation (im not convinced on the last point, I think the air above the liquid, especially in a erlynmeyer flask, would be saturated with co2...

I think ideally you'd have an airstone and a stirrer.

 

[chappo1970]

Interesting point, though I know for sure that my air stone provides nowhere near enough agitation to keep the yeast in suspension - which I believe is one of the main points of a stirrer, along with driving out excess co2 and constant airation (im not convinced on the last point, I think the air above the liquid, especially in a erlynmeyer flask, would be saturated with co2...

I think ideally you'd have an airstone and a stirrer.

Interesting point Sammus.

No stirrer yet (tight one in the pipeline ATM) but I have an airstone .5 micron with pure O2 canister to aerate wort and starters. It would appear that under oxygenation of your wort is much more critical than over oxygenation. Also the only method that achieves the 10pmm O2 level saturation required for healthy yeast growth is an airstone with O2 for 60 seconds. I have been doing mine for 30 seconds as instructed on another thread. So I have been under oxygenating my wort if that's the case? O2 saturation of wort is dependant on OG and temperature. Looks like the colder the wort in the more saturation you get (I gather like CO2 absorbion when Kegging).

But if this is the case I have pitched yeast at a wort only innoculated with 2ml of olive oil. No aeration at all. By all accounts that brew should have done numerous things like not fired, slow fermentation, off flavours, poor ester production etc, etc. I found none of these in that brew. In fact it my case swap Irish Red. I have been getting great comments from those that have tried it (very experienced to the novice brewer) and in fact it has been my favourite brew to date.

So what happened? Why did it turn out so well? I really went against the norm with this one and it turned in spite of all saying it wouldn't, Why?

Referring to my brew notes the yeast was a smack pack 1084 Irish. It fermented out in under 9 days @ 18C. SG1054 to FG1010.

Been doing a little more digging today and found this little snippet on the Wyeast site:




Oxygenation
Oxygen is a critical additive in brewing. Oxygen is the only necessary nutrient not naturally found in wort. Adding adequate oxygen to wort requires a fundamental understanding of why yeast need oxygen, how much oxygen they need, and how to get oxygen into solution and the factors affecting solubility of oxygen.


Why Yeast Need Oxygen Yeast use oxygen for cell membrane synthesis. Without oxygen, cell growth will be extremely limited. Yeast can only produce sterols and certain unsaturated fatty acids necessary for cell growth in the presence of oxygen. Inadequate oxygenation will lead to inadequate yeast growth. Inadequate yeast growth can cause poor attenuation, inconsistent or long fermentations, production of undesirable flavor and aroma compounds, and produces yeast that are not fit for harvesting and re-pitching.

How Much Oxygen?

Oxygen requirement is variable depending on: yeast strain employed, original gravity of wort, and wort trub levels. Some yeast strains have higher oxygen requirements than others. It is generally safe to assume that you need at least 10ppm of oxygen. 10ppm will supply adequate oxygen in most situations. Over-oxygenation is generally not a concern as the yeast will use all available oxygen within 3 to 9 hours of pitching and oxygen will come out of solution during that time as well. Under-oxygenation is a much bigger concern. High original gravity (>1.065) wort, in addition to increasing osmotic stress on yeast, can cause problems with achieving adequate levels of dissolved oxygen. As the gravity of wort increases, solubility of oxygen decreases. Increased temperatures also decrease the solubility of wort. The unsaturated fatty acids found in wort trub can be utilized by yeast for membrane synthesis. If wort trub levels are low, yeast will need to synthesize more of these lipids and therefore will require more oxygen.

Methods of Aeration / Oxygenation Homebrewers have several aeration/oxygenation methods available to them: siphon sprays, whipping, splashing, shaking, pumping air through a stone with an aquarium pump, and injecting pure oxygen through a scintered stone. We have tested all of these methods using a dissolved oxygen meter and have found that, when using air, 8 ppm of oxygen in solution is the best that you can achieve. Injecting oxygen through a stone will allow much higher dissolved oxygen levels. The chart below shows methods tested and the results.

MethodDO ppmTimeSiphon Spray4 ppm0 sec.Splashing & Shaking8 ppm40 sec.Aquarium Pump w/ stone8 ppm5 minPure Oxygen w/ stone0-26ppm60 sec (12ppm)

It was concluded that pumping compressed air through a stone is not an efficient way to provide adequate levels of DO. Traditional splashing and shaking, although laborious, is fairly efficient at dissolving up to 8 ppm oxygen. To increase levels of oxygen, the carboy headspace can be purged with pure oxygen prior to shaking. The easiest and most effective method remains injecting pure oxygen through a scintered stone.


Anyways I must continue but I would like to debate this further with more of the brewing brains trust as to this method of aeration.

Cheers


Chappo

 

[muckanic]

As Wyeast kind of acknowledge, it may well be possible to achieve 26 ppm using O2 injection, but a practical issue is what happens next, ie, how long does that concentration remain in the brew? When they say that yeast needs 10 ppm, it is not clear whether they mean a constant 10 ppm during the growth phase or a single shot of 10 ppm at the start of the growth phase.

 

[chappo1970]

Exactly Muckanic, they go on to qualify "Over-oxygenation is generally not a concern as the yeast will use all available oxygen within 3 to 9 hours of pitching and oxygen will come out of solution during that time as well". So I take that meaning the yeasts only need oxygen present for between 3 to 9 hours at say 10ppm. So over oxygenation is good but what does "yeast will use all available oxygen" mean? How long does oxygen remain in suspension in a wort solution?

Also does that mean say if you had a fish tank aerator with an airstone that you could say run it for the first 6 hours of primary fermentation?

Chappo

 

[mika]

This debate has been big on the american sites and the Brewing Network actually spoke to some Belgian brewers who were experimenting with it on a larger scale (by larger, we're still not up to the size of most Australian microbrewers if IIRC).
The results showed merit, but they went to lengths to say that it is not a direct replacement for, or even as good as dissolved oxygen. My understanding from the discussions is that it's possibly better than no aeration, otherwise it really only applies to packaging breweries or people wanting to keep beer in bottles in good condition.

Chappo - One brew does not an experiment make. Try a few and then plot the curve to the data, not the data to the curve.

 

[Nick JD]

So, if the wort has zero dissolved oxygen but you pitch the motherlode of yeast, fermentation will be fine?

Or if you add a teeny bit of olive oil and under pitch (again, zero dissolved oxygen) you'll get good fermentation?

Olive oil sounds great way with no chill...

 

[mika]

So, if the wort has zero dissolved oxygen but you pitch the motherlode of yeast, fermentation will be fine?

Kinda, not really. Some yeast growth for ester production isn't a bad thing, but theoretically, yes.

Or if you add a teeny bit of olive oil and under pitch (again, zero dissolved oxygen) you'll get good fermentation?

You'll get OK fermentation, or at least that's where the debate begins.

 

[MartinS]

Something I don't understand here is the difference between what the research says, and what you guys are doing. You guys are adding a couple of millilitres of oil, right? Doesn't the research say we should be adding single-digit milligrams for our quantities?

I'm sure I'm missing something here, but it seems to me people are adding about a thousand times the recommended dose.

 

[Bribie G]

I used the olive oil method in my latest brew, about a ml, and it's gone off like a rocket on US-05 without the normal splashing and paddling I do (I'm a no chiller and normally would give the wort a good splash and thrash when transferring from cube to fermenter before pitching)

 

[chappo1970]

...Chappo - One brew does not an experiment make. Try a few and then plot the curve to the data, not the data to the curve.

Totally agree mika and there is one thing for sure I don't profess to be a scientist or a researcher. Plus in my brewery environment there would be no way of accurately quantifying any of my results. I do however have a very keen interest in this method and am willing to keep going on a trial and error basis. It would be great if one or two of our more technically advanced minded brewers could maybe pick up the gauntlet but I guess that would near impossible.

Something I don't understand here is the difference between what the research says, and what you guys are doing. You guys are adding a couple of millilitres of oil, right? Doesn't the research say we should be adding single-digit milligrams for our quantities?

I'm sure I'm missing something here, but it seems to me people are adding about a thousand times the recommended dose.

No you are right and wrong. If you look at the original thesis, they state that they did several tests, ranging from 1 ml of oil per 67 Billion yeast cells to 1 ml of oil per 25 billion yeast cells. A smack pack is 100 billion yeast cells, so this implies about 1.5 to 4 ml of oil would be added for one smack pack. I think packs of dry yeast are a similar size, so this is still OK. Therefore it appears to be spot on with 3 ml or less. They also added oil to starter 5 hours before pitching. (snip from Hazzard post on another thread)

Cheers

Chappo

 

[brettprevans]

ahh now lets really throw an interesting question into the debate...... will the olive oil work in something like a mead where constant oxygenation is a must. that would be some interesting testing

 

[chappo1970]

ahh now lets really throw an interesting question into the debate...... will the olive oil work in something like a mead where constant oxygenation is a must. that would be some interesting testing

Wow? I think my rather small brain just slipped a cog on that one CM2. :huh:

Hmmm????? :blink:

Chappo

 

[alowen474]

I used the olive oil method in my latest brew, about a ml, and it's gone off like a rocket on US-05 without the normal splashing and paddling I do (I'm a no chiller and normally would give the wort a good splash and thrash when transferring from cube to fermenter before pitching)

If the yeast is dried, is it not conditioned to do its job without aeration?

 

[Supra-Jim]

Chappo,

Would not be possible to get a reasonable approximation (with an acceptable degree of error for the home brewer) by using a stir plate, air stone + cylinder, olive oil, same strain of yeast and same starter.

Your two variables would be 02 or olive oil and with the starter, you could get a reasonable approximation of the growth of the yeast (i.e without trub from a full fermentation). These could even be fermented side by side in a double batch split between two fermenters.

I think given (as you stated) the 'wiggle room' in our equipment etc, an experiement like this should be able to produce a resonably acceptable result. Evidence could be seen in the yeast grown in the starter and that could also be compared against the fermentation results (OG vs FG etc).

Food for though?

Cheers SJ