Brewing Several days in a row... Experience at a local brewery

[william_shakes_beer]

Do some googling on DFH120IPA and people how have done homebrewed versions...they are oxygenating up to a month after the first pitch, concurrent with additional yeast/fermentables/hops pitches. Its not uncommon when "feeding" ultra-high gravity beers, the trick here is to have active yeast to metabolize the the oxygen.

It is common for people to take recommendations/guidelines and petrify them into hard and fast rules. In this case, the actual rule should be "don't introduce oxygen if the yeast activity level isn't sufficient to metabolize it" not "NEVER add oxygen after a yeast pitch".

Thanks for the clarification on oxygenation. I was up until today one of those "don't add o2 after pitch" folks, but your comment makes sense. If the yeast is still active they metabloize the oxygen.

Of course your punishment for answering a question is you get another question. Common wisdommis that if you add oxygen post fermentation you get oxidation and off flavors. What is the chemical mechanism for this? are the o2 molecules binding to the (proteins? residual sugars?) Why doesn't the excess oxygen simply of-gas like excess co2?

 

[broadbill]

Thanks for the clarification on oxygenation. I was up until today one of those "don't add o2 after pitch" folks, but your comment makes sense. If the yeast is still active they metabloize the oxygen.

Of course your punishment for answering a question is you get another question. Common wisdommis that if you add oxygen post fermentation you get oxidation and off flavors. What is the chemical mechanism for this? are the o2 molecules binding to the (proteins? residual sugars?) Why doesn't the excess oxygen simply of-gas like excess co2?

Oxygen is an oxidizer, and can efficiently "attack" and and oxidize any number of molecules in the beer: ethanol to acetylaldehyde, hop acids to short chain fatty acids, and unsaturated fatty acids, etc.

It doesn't off-gas because beer wort has some capacity to be saturated with oxygen. It is released but at a rate that is influenced by a number of factors (temperature for example).

 

[mliptack]

Do some googling on DFH120IPA and people how have done homebrewed versions...they are oxygenating up to a month after the first pitch, concurrent with additional yeast/fermentables/hops pitches. Its not uncommon when "feeding" ultra-high gravity beers, the trick here is to have active yeast to metabolize the the oxygen.

It is common for people to take recommendations/guidelines and petrify them into hard and fast rules. In this case, the actual rule should be "don't introduce oxygen if the yeast activity level isn't sufficient to metabolize it" not "NEVER add oxygen after a yeast pitch".

I have heard about adding O2 on day 2 on the Jamil Show (for high gravity beer). So in effort to contain the responses, this brewer said this is standard practice for him so let's keep this discussion to beers with more delicate flavors / lower gravities.

What you are saying makes perfect sense, only add enough O2 that the yeast are able to metabolize, but again you are bringing the discussion to a stronger beer. This brewer used the same process for all the brews. Which is why I wanted to take the conversation away from the stronger beers and concentrate on the beers with more delicate flavors & lower gravities.


With that said, I want to comment on the brews themselves.

I bought 3 samples.
1- Wheat
1- Double IPA
1- Porter

The wheat beer had a good flavor and a nice malty aroma. But seemed to lack body mouthfeel and complexity - probably over attenuation. The beer was clear. Light straw color. It had an overly strong hop presence/bitterness, almost like a session IPA, but this was likely because of the lack of a balance due.

The IPA - Was expectedly hop forward, seemed to have more of a earthy hop flavor. This beer had a ABV reported in the 9-10 range, but again lacked complexity. It was bland. This beer had the most body of the three. I bought a growler of this beer. I drank 3/4 of the growler in an evening (I certainly didn't feel like it was in the 9%+ range!)

The porter - Was very dry, almost black-coffee like astringency. Again, (you guessed it) almost no body. WAY over attenuated.

I finished all the samples of the beer - the beer wasn't undrinkable by any means, but it wasn't something to write home about. I just wondered how their process would affect it all.

The lack of body seemed like the common denominator - like it was caused by an over pitch to start with. From what I read/ and hear on the Jamil Show / TBN, as a rule of thumb yeast will double their cell count in 24 hours. Plus an excess of O2 will cause the yeast to focus on increasing the cell count instead of fermenting - eating sugars and O2 (but not creating CO2 yet - hence the lag time after pitching yeast). After the first 24 hours you have a cell count that is ready to ferment 30-40bbls and you add more wort and O2, then focusing the yeast's attention to propagation rather than fermentation....

This is why I think most of the beers lacked body. Additionally, it could be a cause for the IPA having a deceptively high ABV.

Or all of this could be caused by an inexperienced brewery without a good recipe to start with...

Cheers,
Max

 

[mliptack]

Correction - I stated the beer was s porter. It was in fact an oatmeal stout.

Now that I think about it again, it had a smokiness (maybe a very small % of a smoked malt)