Olive Oil - Testing

[ajdelange]

I am not saying that you should (or shouldn't) look for an olive oil flavor. I'm just trying to point out that you can be quite flexible in what you can determine from a properly conducted test. The basic test has a null hypothesis that reads something like "Use of olive oil as opposed to normal oxygenation has no effect on beer." If you find, on the basis of test panel data, that the null hypothesis should be rejected it is natural to want to know why. That's what the secondary question(s) are for.

 

[Warthaug]

I realize this is somewhat OT for the thread, but I've been experimenting with OO as a supplement in the media I use to prepare yeast stocks for freezing. I maintain a large-ish yeast bank for my local brewclub (details in my blog, if anyone wants the details), and have been trying to find ways to maximize viability of yeast post-freezing. My normal growth medium is DME @ 1.040 + a zinc supplement at the manufacturers recommended dose. To this I added 0.1ml/L OO. Yeast were grown on a shaker to maximize oxygenation. My rational was essentially to allow the yeast to maximize their production of glycogen/sterols by minimizing their need to synthesize unsaturated fatty acids.

I did a side-by-side, growing wyeast 1056 normally or with OO, freezing at -80C in 1.040 wort + 20% glycerol, and then thawing a sample and using trypan blue to test for post-freezing viability, and I did a post-freezing growth test. The difference in viability was negligible - 68% (normal) vs. 71% (OO), but the OO yeast did come out of lag phase a little faster (budding yeast were observed after 3.5hrs (OO) vs. 5hrs (normal)). This may represent larger glycogen stores or less freezing stress.

It would be interesting to see the effect of this on a starter; in theory you may get larger yeast numbers or happier yeast. I'm not sure I'd want to add OO directly to the fermenter, just because of the potential impact on head retention.

Bryan

 

[luke2080]

In theory, yes the yeast can metabolize it. My question is do they have access to it? Does the oil disperse well enough into the wort so the yeast have access to it? If it just floats on top, it won't be taken up very rapidly by the yeast.

Taste testing aside - This is the point of capturing the FG results. Without proper aeration it is tougher for the yeast to fully attenuate to the degree planned. So capturing the FG of the OO version and different versions of other aeration methods is the most meaningful testing of this, IMO. Without sending every sample for a full lab diagnostic.

I plan to run my taste tests using the triangle method. Should be easy enough - pick out the odd beer, than compare the odd beer with the other.

If the use picks the odd beer incorrectly - are all of their taste test results afterwards (which is bettter, was their off flavors, fruitier, more bitter, etc) then null and void?

I'll tweak the initial instructions to account for this. Makes sense to do that.

I do hope those of you providing feedback run this test a time or two this year as well!

I should have results from my first batch following the tighter control in 3-4 weeks. And will do this with every batch this year.

 

[Denny]

If the use picks the odd beer incorrectly - are all of their taste test results afterwards (which is bettter, was their off flavors, fruitier, more bitter, etc) then null and void? .

Correct!

 

[jesserizzo]

Could this be done in a more objective manner? Something like: make 2 yeast starters, one only with OO, the other on a stir bar. Then do a cell count of both starters. Dump in a measured amount of something toxic to yeast, I'm thinking vodka. Do another cell count. Theoretically, if the OO does as good as traditional aeration, they should have similar amounts of dead cells.

 

[broadbill]

Could this be done in a more objective manner? Something like: make 2 yeast starters, one only with OO, the other on a stir bar. Then do a cell count of both starters. Dump in a measured amount of something toxic to yeast, I'm thinking vodka. Do another cell count. Theoretically, if the OO does as good as traditional aeration, they should have similar amounts of dead cells.

why is killing the cell necessary? Shouldn't the first measurement be adequate to prove your hypothesis?

Also, killing the cells may be another step at which OO may have an effect; if it does have an effect it might be difficult to interpret the results of OO's cumulative effects.

 

[ajdelange]

If the use picks the odd beer incorrectly - are all of their taste test results afterwards (which is bettter, was their off flavors, fruitier, more bitter, etc) then null and void?

If a panelist can't tell whether one beer is different from another how can he tell whether it is sweeter or fruitier than another?

If you are going to do a triangle test you will need to be able to compute the confidence levels associated with your observations. There are tables or you can use a spreadsheet such as this one:
http://wetnewf.org/pdfs/Brewing_articles/Triangle.xls

 

[broadbill]

Taste testing aside - This is the point of capturing the FG results. Without proper aeration it is tougher for the yeast to fully attenuate to the degree planned. So capturing the FG of the OO version and different versions of other aeration methods is the most meaningful testing of this, IMO. Without sending every sample for a full lab diagnostic.

The effect of OO on FG vs. normal aeration is already known (no difference). OO appeared to slow the kinetics of fermentation however-OO took longer to reach FG.

What exactly are you trying to demonstrate, that hasn't already been done? Just that this also happens at the home-brew level? Is there any reason to believe that it doesn't?

 

[jesserizzo]

why is killing the cell necessary? Shouldn't the first measurement be adequate to prove your hypothesis?

Also, killing the cells may be another step at which OO may have an effect; if it does have an effect it might be difficult to interpret the results of OO's cumulative effects.

Yeah, just counting the cells might do it. I feel like introducing a toxic element helps us determine if the cells are as strong as with traditional aeration is another useful data point.

It seems to me that this test should definitely be done before the full batch taste tests. If you already have a microscope and cell counting thing, it could be done for a few bucks and in 2 or 3 days.

 

[broadbill]

Yeah, just counting the cells might do it. I feel like introducing a toxic element helps us determine if the cells are as strong as with traditional aeration is another useful data point.

What you need to do is test a range of ethanol concentrations.

The problem with using a single concentration that kills 100% of the control cells is that it will be pretty darn toxic to the OO yeast, even if the hypothesis is correct that OO makes yeast more resistant. It is tough to see a significant difference in this experiment. The same goes for a too low concentration of ethanol.

The standard measurement for these studies is LD50, the dose of toxin that causes 50% lethality. Then compare LD50 of control versus OO yeast. Differences in that value tell you if OO has the effect of making yeast more resistant to ethanol.

If you already have a microscope and cell counting thing, it could be done for a few bucks and in 2 or 3 days.

I disagree, based on my explanation above. It is a much more detailed experiment to do it correctly.

 

[WoodlandBrew]

What you need to do is test a range of ethanol concentrations.

The problem with using a single concentration that kills 100% of the control cells is that it will be pretty darn toxic to the OO yeast, even if the hypothesis is correct that OO makes yeast more resistant. It is tough to see a significant difference in this experiment. The same goes for a too low concentration of ethanol.

The standard measurement for these studies is LD50, the dose of toxin that causes 50% lethality. Then compare LD50 of control versus OO yeast. Differences in that value tell you if OO has the effect of making yeast more resistant to ethanol.

I disagree, based on my explanation above. It is a much more detailed experiment to do it correctly.

I've done similar types of tests including ABV effects on yeast. You can see the results here:
http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html

Testing the effects of olive oil on attenuation is intriguing, although like others said, it has been done. If I was going to test it I would want to look at a fermentation with a high potential to stall and have a control that is not aerated and without olive oil that should stall as a comparison. It would have to be conducted in triplicate at a minimum and I would probably look at a few inoculation rates and gravities as well. These kind of tests take several hours to set up. 15-30 minuets per day to monitor progress and several hours at the end to collect the results. Then there are normally several hours of data processing and write ups. Also, if you are trying a new technique, or haven't done this type of testing before chances are that it will not produce adequate data.

Anything short of this level of testing leaves too many question marks in my mind.

But as for the test on the flavor effects as is being discussed in this thread. I think that's a great idea. I hope that there are enough people willing to contribute.

 

[Wynne-R]

I’m bottling my olive oil experiment today. I was surprised to see they look different. They taste different too. The picture was taken at eleven days. OO is the one on the left.

Both batches started at 1.062 and finished at 1.017. The yeast was one day old slurry. The slurry was divided and warmed to pitching temperature. One starter got two drops of olive oil. Both fractions (200mL) got five hours (alternately) on the stirplate with 150 mL of fresh wort.

Both batches were poured through a funnel into five gallon carboys. That was the only aeration.

I’ll post tasting results when they’re available

 

[luke2080]

I’m bottling my olive oil experiment today. I was surprised to see they look different. They taste different too. The picture was taken at eleven days. OO is the one on the left.

Both batches started at 1.062 and finished at 1.017.........
I’ll post tasting results when they’re available

Nice. My first batch for this test is being bottled this weekend as well. The version with OO was 2 points lower 10 or 14 days in, but both finished the same. Will post that as I have tasting results...and at that time I'll setup a google doc or something to record results.

 

[luke2080]

Honey-Orange Hefe - using WLP300

OG 1049
Batch w/ OO = FG 1010
Batch w/out = FG 1010

3 Taste testers, triple blind. 1 could not pick the beers that matched. Of the other 2 results, one preferred the OO, and one the batch w/out. But all comments were really that it was identical.

The batch with OO after 1 week was two points lower, but that was the only difference. Will keep putting these results, and other posted results, to an excel sheet.

 

[Denny]

Honey-Orange Hefe - using WLP300

OG 1049
Batch w/ OO = FG 1010
Batch w/out = FG 1010

3 Taste testers, triple blind. 1 could not pick the beers that matched. Of the other 2 results, one preferred the OO, and one the batch w/out. But all comments were really that it was identical.

The batch with OO after 1 week was two points lower, but that was the only difference. Will keep putting these results, and other posted results, to an excel sheet.

Thanks. No surprise for me.

 

[Wynne-R]

I am surprised, that is very different than my preliminary informal test.

I sprung a couple of bottles on some experienced judges. They only knew that it was an experiment with one slight difference.

They all thought the difference was in the hops. Four preferred the OO sample, one liked the regular, one had no preference. All perceived a substantial difference.

I will be running a large scale double blind test soon. Stay tuned !

 

[DocG308]

After going through this thread, I would like to add some points to ponder:
1) what kind of olive oil are you using? This is actually very important. The grades of oil have highly different flavors and robustness.
2) most olive oils sold in the US have been adulterated with grain oils, such as corn or canola. These oils have acids and oxidizers that can change the flavor of your beer. Since you don't know what oils or how much was used in your bottle of olive oil, the effect is unmeasurable because of its random nature.

My 2 pennies...
Doc

 

[broadbill]

After going through this thread, I would like to add some points to ponder:
1) what kind of olive oil are you using? This is actually very important. The grades of oil have highly different flavors and robustness.
2) most olive oils sold in the US have been adulterated with grain oils, such as corn or canola. These oils have acids and oxidizers that can change the flavor of your beer. Since you don't know what oils or how much was used in your bottle of olive oil, the effect is unmeasurable because of its random nature.

My 2 pennies...
Doc

The effect of different grades/types of olive oils when olive oil appears to have no effect in the first place...is still no effect...

 

[Denny]

The effect of different grades/types of olive oils when olive oil appears to have no effect in the first place...is still no effect...

Not to mention that if you use enough to taste differences, you've used too much.

 

[Wynne-R]

I have the results from the large scale double blind test. The audience survey split roughly in thirds. They had no idea what they were testing, or even if they were different. Sample size 75.

1. Prefer OO 37%
2. Prefer regular 32%
3. No preference/no difference 29%

Afterward I talked to individuals and asked if they had a favorite. The OO fans found it hoppier, brighter and sweeter. Regular was described as crisper drier and more balanced. The people that perceived a difference described it as substantial.

I am planning a triangle test soon.

 

[Denny]

I have the results from the large scale double blind test. The audience survey split roughly in thirds. They had no idea what they were testing, or even if they were different. Sample size 75.

1. Prefer OO 37%
2. Prefer regular 32%
3. No preference/no difference 29%

Afterward I talked to individuals and asked if they had a favorite. The OO fans found it hoppier, brighter and sweeter. Regular was described as crisper drier and more balanced. The people that perceived a difference described it as substantial.

I am planning a triangle test soon.

How old was the beer they tasted?

 

[Wynne-R]

Brewed Feb 17, bottled Feb 29

 

[Wynne-R]

How 'bout this for the triangle ?
---------------------------
Triangle Test

Which one’s different?
(Circle)

A B C

D E F


Different how?
Indicate more or less If same leave blank

Hoppy

Malty

Estery

Sweetness

Crispness

Head

Body


Comments -

 

[Denny]

Brewed Feb 17, bottled Feb 29

Any plans to retest in a few months?

 

[Denny]

How 'bout this for the triangle ?
---------------------------
Triangle Test

Which one’s different?
(Circle)

A B C

D E F


Different how?
Indicate more or less If same leave blank

Hoppy

Malty

Estery

Sweetness

Crispness

Head

Body


Comments -

At first glance it looks good to me, but in doing these I've found it's best to think about it for a while before settling on questions. You need to make sure you're getting all the info you need and not biasing the answers.

 

[broadbill]

Maybe ask the tastier to rank the beers in regard to each adjective you list: i.e. For hoppiness: B>C but B=A.

That could give you categorical columns to tally up in Excel?...maybe?

 

[Denny]

The other thing is to use AJ's spreadsheet to determine how the choices would rank according to chance.

 

[Wynne-R]

Denny, I hadn’t planned on saving any, My pales are best at 6-8 weeks. I'm shooting for 40 trials, which ought to take most of the remaining beer.

broadbill, I thought that was implied. Is this more clear? I want this to be as simple as possible, for me and everybody.

----------------------------------------------------------------------------
Different how?
How is the one you picked different than the other two?
Indicate more+ or less- If same, leave blank
----------------------------------------------------------------------------

No spreadsheets for me. I’d rather do the math. In this case I’ll try to find someone to do it for me. What I know about probability I learned playing poker.

 

[Denny]

The reason I asked is because IIRC both NB and Vance found significant deterioration in OO bbers over time. I'd have to double check to ne sure of that, though. And I think itwould reallky be worth your while to look at the spreadsheet that AJ has for triangle tasting.

 

[Wynne-R]

Well that’s news to me. I thought those experiments were done with the toothpick method, which I would expect to show no difference at all.

To be clear, we’re talking about a drop or two in the starter on this thread.

AJ’s spreadsheet won’t run on my computers. I have QuattroPro because it was free with WordPerfect, but it’s not completely compatible with Excel.