Oxidation experiment, unexpected results

[Sadu]

Soooo, long story short I have been experiencing this malty rich flavour in my brews (mostly lagers) that I can't quite seem to pick, and I thought be the "sherry" flavour that people talk about regarding oxidation.

Except I don't know what oxidation tastes like as I don't regularly eat wet cardboard so I thought it would be good to do a little experiment and find out first hand.

So I bottled a 1.035 brown ale a couple of weeks ago. This was a bit of a "leftovers" batch made from frozen RIS 3rd runnings and some frozen starter wort I had on hand. I'll say now it's not my best work to date, but I figured it didn't have any strong flavours to get in the way of the test.

On bottling day I took one bottle and with my thumb over the top shook the thing like my life depended on it. Then removed my thumb to let in fresh O2 and shook it again. Repeated this for a couple of mins, then capped the bottle about 3/4 full so there was a crazy amount of headspace. It was total beer abuse.

Tonight I did a blind tasting. Got the kids to serve me blind and I had a taste. I was expecting to get hit by wet cardboard, or possibly sherry to verify my lager off-flavour.

No such luck. Both samples tasted exactly the same to me. Clean sample had better head on it but that was the only diifference I could pick.

- So either my beer-handling process is so bad that the whole batch was oxidised and shaking the hell out of one bottle made no difference.
- Or my palate is so bad that I can't taste the difference between a clean beer and a heavily oxidised sample.
- Or oxidation somehow isn't apparent 1.035 brown ales with minimal hopping.
- Or oxidation needs more than 2 weeks to manifest itself as an off-flavour.
- Or there was something else flawed with my testing logic.
- Or oxidation is an imaginary boogeyman that is used to scare new brewers.

I'm not saying that anything conclusive can be drawn from this. All I'm saying is that I can't taste the difference between these 2 beers, which are identical aside from one being very carefully handled at bottling time and the other one agitated to bring in as much O2 as possible.

Clean sample is on the left. I'm gonna repeat this on my tasty simcoe/amarillo pale ale which has 8oz of hops and see what happens there.

 

[timdillon36]

Oxidation is a real thing. HSA is up for debate still.

At 2 weeks in the bottle you won't notice the o2 much but over time in the bottle it will go down hill.

If you want to try this on your pa I would suggest when there is about a 6 pack left in the bottleing bucket use a wisk and beat it like it owes you money.

Then do a blind taste every month.

 

[Sadu]

If you want to try this on your pa I would suggest when there is about a 6 pack left in the bottleing bucket use a wisk and beat it like it owes you money.

Haha, nice idea, except the pale ale is a 1 gallon batch and my yield is about 7 pint-bottles.

But your point is noted though - I gave that bottle a good thrashing and gotta say I was expecting at least some wet cardboard. But if it takes more time to show up then that makes sense and I'll leave it longer next time.

I guess a brew club would be handy for this kind of thing. Been thinking about starting one, and being able to try other people's off-flavours would strangely be one of the highlights :rockin:

On the plus side, since this malty rich lager flavour shows straight away and we are saying that oxidation might take several weeks to manifest, maybe oxidation isn't the droid I'm looking for?

 

[jschein]

If you want to test your palate for different off flavors there are kits for that https://www.siebelinstitute.com/products/sensorykits/

 

[Derp]

I've struggled with oxidation problems and much of it was because of the "wet cardboard" taste that I'd read about but never experienced. My beers, especially the hoppy ones, would smell/taste great as soon as I kegged them, but the hops faded quickly and the beer lost all of its character. I thought my kegging process was good (CO2-purged keg filled via liquid post) and I never detected a cardboard taste, so I wasn't sure what was gong wrong. Then one day I noticed that an IPA had darkened significantly and I knew it had to be oxidation.

I started dosing each corny with 200 mg of sodium metabisulfite per a thread on HBT and also changed my drop hop routine to begin after the beer was 80% fermented. Previously, I added dry hops after fermentation was complete.

My beers are noticeably better these days and I'm hoping they stay that way. They're so tasty that I'm not sure I'll be able to see how they hold up after a month or two, however.

 

[LKABrewer]

Oxidation is accelerated by heat. Take some of those bottles and warm them up to 100f for a day or two and you will taste the oxidation much better.

 

[eric19312]

Bottle conditioning should help minimize oxidation since the yeast will consume some of the oxygen. I think oxidation is more of an issue when you force carb kegs.

 

[Yooper]

I've heard oxidation described as "wet cardboard" as well, but even as a beer judge with lots of beers suffering from oxidation, I think I've only tasted that once.

Generally, oxidation effects seen are an early staling of flavors, and loss of character. The beer won't be as "fresh" and "bright". Then, hops flavors fade and the beer may start to have a hint of "brandy" flavor to it. As oxidation gets worse with age, the color of the beer can start to darken and then the flavor gets more like madeira or even sherry, or more brandy-like with a sweetness to it. In beers that are aged a long time, on purpose, like barley wines, this is part of the flavor profile and desirable but in most other beers, it's a flaw.

The main reason to be concerned about oxidation at the homebrew level is more about the freshness or inhibited staling effects, if we don't drink our beers quickly. Oxidation and staling reactions accelerate with higher temperatures and with time, so a fresh beer may not have severe oxidation flavors even if treated poorly.