How to avoid NEIPA oxidation?

[Hazelwood Brewery]

I haven’t done any research into this but from a cursory review it looks like they may be using ascorbic acid in the mash to reduce the metal ions produced during the mash and that survive through to the finished beer. These metal ions are pro-oxidative and lead to oxidation of your beer.

I do the same thing by mash hopping with high AA hops, the acids “complex” those metal ions so they are no longer pro-oxidative (the binding sites are already occupied).

 

[Tess Tickle's Brewery]

I haven’t done any research into this but from a cursory review it looks like they may be using ascorbic acid in the mash to reduce the metal ions produced during the mash and that survive through to the finished beer. These metal ions are pro-oxidative and lead to oxidation of your beer.

I do the same thing by mash hopping with high AA hops, the acids “complex” those metal ions so they are no longer pro-oxidative (the binding sites are already occupied).

Very interesting!

Going to keep doing what I'm doing.

 

[DocAnna]

Here is the video I was talking about. I think I misunderstood why they were putting it in the mash. I get it now.

Out of curiosity, what temperature do you store your neipas at?

I'm really sorry but he is misinterpreting the evidence about the oxidation, and the boil destroys the Vit C in minutes. The increased oxidation spoken about is of the Vit C - which is entirely the point, ie it oxidises, but not the other oxidation sensitive compounds.

I've gone back and read around this more, having previously posted on the science of this.
There is a small scale study, so needs caution in interpreting the result, that shows the best time to add Vit C is after the wort is cooled. I'm not entirely convinced that the scale of the study was powered to detect the differences they were looking for, however, the point being that in all scenarios, the vit C is added after the boil.

Jeney-Nagymate, E. and Fodor, P. (2007) ‘Examination of the Effect of Vitamin E and C Addition on the Beer's ESR Lag Time Parameter’, Journal of the Institute of Brewing, 113(1), pp. 28–33. doi:10.1002/j.2050-0416.2007.tb00252.x.

The biggest issue is that Vit C is highly temperature dependent in solution. At mash temperature it will degrade but to be fair there will still be some in solution at the end of a 60min mash, the issue is the boil. Degredation of ascorbic is first order kinetics on temperature, so it gets degraded proportionally faster with temperature. At 90°C, the half life is 10 mins, and even faster at the boil temperature.

There are other factors that make boiling ascorbic acid not a good idea:
Yin, X.; Chen, K.; Cheng, H.; Chen, X.; Feng, S.; Song, Y.; Liang, L. Chemical Stability of Ascorbic Acid Integrated into Commercial Products: A Review on Bioactivity and Delivery Technology. Antioxidants 2022, 11, 153. Chemical Stability of Ascorbic Acid Integrated into Commercial Products: A Review on Bioactivity and Delivery Technology

The degradation or oxidation products of ascorbic acid heated at 100 °C for 2 h include furfural, 2-furoic acid, 3-hydroxy-2-pyrone and an unknown compound. Among them, furfural is one of the main degradation products of ascorbic acid, which can polymerize or combine with amino acids to form brown melanoids, causing the browning of ascorbic acid-containing juice products [62]. Furthermore, thermally oxidized ascorbic acid was identified as a potential precursor of furan; it is a possible carcinogen usually produced in some heated food products [71]. Meanwhile, natural and synthetic antioxidants, such as chlorogenic acid, have a certain mitigation effect on the formation of furan induced by heated ascorbic acid, but the mitigation effect may decrease with the increase in heating time [72]. In addition, the thermal degradation process of ascorbic acid is also affected by pH, oxygen concentration, transition metal ions and oxidases, which is a complex system.

As for hot side oxidation - and whether it exists or not, that is for another day.

 

[Agentgonzo]

At mash temperature it will degrade but to be fair there will still be some in solution at the end of a 60min mash, the issue is the boil.

Wasn't there something about the AA preventing stuff from forming during the mash that would otherwise continue through to the final product and then oxidise the beer? So if (and that's a colossal if) the AA has done its job during the mash, it doesn't need to survive the boil? Otherwise he would presumably () have added the AA to the boil?

(I don't understand the Chemistry of what adding the AA during the mash does, but I'm fairly confident the guy in the video doesn't either )

 

[DocAnna]

(I don't understand the Chemistry of what adding the AA during the mash does, but I'm fairly confident the guy in the video doesn't either )

I hope most people will realise by now I try to steer well clear of being derogatory in any way about anyone here or in general. It's just not my thing.

However. That video is the most junk science irresponsible nonsense I have seen since Trump described injecting sunlight and bleach to cure COVID. Ok I will now feel awful about myself for having said this, as normally I just stay out of it (hence not commenting on health topics).

 

[Sadfield]

A little bit of acerbic can be useful.

 

[JockyBrewer]

Pretty much any anti oxidative step you can take pre-fermentation in the brewing process is undone in as little as a few seconds of careless handling post fermentation, so personally that's where I think most home brewers should be concentrating their energy.

 

[Clarence]

Post #48
So after learning that he thinks there are two types of Vitamin C, that 3-5 grams in the mash is enough for 20 gallons and that he doesn't fully understand the science, we're left wondering what we've gained from this video.

That's the trouble with being interrupted half way through a post, it's unbalanced.
I didn't realise, and I've never heard it mentioned before, that using crystal malts promotes oxidation in the packaged product. My experience with bottled bitters is that they can taste alright to start with and then that "cloying sweetness" really can set in. Any comments on this, anybody?
He mentioned that ascorbic acid promotes the formation of two sets of compounds in the mash (I can't bear to go through it again) which help prevent oxygen damage in the early parts of the process. Is this the case?
Following advice from other members of this forum, I did start adding ascorbic acid at bottling time. I'm not sure it made much difference and then I read that sulphite levels also needed to be raised otherwise the vit C would promote oxidation. So I stopped.

 

[AJA]

Yep. I wouldn't fancy pulling any of that through a corny poppet.

It works 50% of the time. The other 50 it gets blocked and whilst easy to unblock, will instantly get reblocked.
I use bags in my corny now.

 

[Sadfield]

It works 50% of the time. The other 50 it gets blocked and whilst easy to unblock, will instantly get reblocked.
I use bags in my corny now.

The introduction of oxygen into the dip tube/transfer line whilst unblocking, would make it counterproductive. I use a filter around my dip tube, on the rare occasions I hop in the keg.

 

[Hazelwood Brewery]

That's the trouble with being interrupted half way through a post, it's unbalanced.
I didn't realise, and I've never heard it mentioned before, that using crystal malts promotes oxidation in the packaged product. My experience with bottled bitters is that they can taste alright to start with and then that "cloying sweetness" really can set in. Any comments on this, anybody?
He mentioned that ascorbic acid promotes the formation of two sets of compounds in the mash (I can't bear to go through it again) which help prevent oxygen damage in the early parts of the process. Is this the case?
Following advice from other members of this forum, I did start adding ascorbic acid at bottling time. I'm not sure it made much difference and then I read that sulphite levels also needed to be raised otherwise the vit C would promote oxidation. So I stopped.

That’s right, ascorbic at bottling - as late in the process as practical.

 

[Agentgonzo]

I didn't realise, and I've never heard it mentioned before, that using crystal malts promotes oxidation in the packaged product. My experience with bottled bitters is that they can taste alright to start with and then that "cloying sweetness" really can set in. Any comments on this, anybody?

I've never noticed any cloying sweetness with any beers that use crystal malts (of which a lot of British ales do).

I'm not sure it made much difference and then I read that sulphite levels also needed to be raised otherwise the vit C would promote oxidation. So I stopped.

I dug deep on this one. All I could find about Ascorbic's 'super-oxidiser' properties were just people on reddit/forums saying "they had heard it somewhere else" and just parroting the information. I also found that this might be true if the fermentation medium is low in sulphur (hence the need to add SMB). Wine must is naturally low in sulphur (where I think that this 'information' came from) but beer is not.
So as best I can find out, the promotion of oxidation/super-oxidiser properties of AA do not happen in beer and people have read about it in wine, and just started saying the same thing about beer.

 

[AJA]

The introduction of oxygen into the dip tube/transfer line whilst unblocking, would make it counterproductive.

Oxygen won't get through. Dip tube is full of crud (mainly yeast which I dump with a party tap pre transfer), and also has a minute surface area anyway so oxygen exposure almost minimal. I'm only unblocking the post rather than the tube.

 

[JockyBrewer]

The introduction of oxygen into the dip tube/transfer line whilst unblocking, would make it counterproductive. I use a filter around my dip tube, on the rare occasions I hop in the keg. View attachment 81308

I have exactly the same setup with using one of those keg hoppers to filter the dip tube so hops can float loose when I'm dry hopping in the keg. Works really well - 150g dry hop has been no problem.

When unblocking a dip tube I blow CO2 down it. Just be very careful what you're doing if you do that as you don't want beer coming up the gas line into your regulator. Either use a non return valve or keep the gas line at a higher pressure than the keg at all times.

 

[AJA]

I have exactly the same setup with using one of those keg hoppers to filter the dip tube so hops can float loose when I'm dry hopping in the keg. Works really well - 150g dry hop has been no problem.

When unblocking a dip tube I blow CO2 down it. Just be very careful what you're doing if you do that as you don't want beer coming up the gas line into your regulator. Either use a non return valve or keep the gas line at a higher pressure than the keg at all times.

I've seen this solution before and it looks really neat. Better than putting the hops in the hopper as they get more exposure to beer. Will give it a try when my AliExpress order arrives.

 

[Tess Tickle's Brewery]

That video is the most junk science irresponsible nonsense I have seen since Trump described injecting sunlight and bleach to cure COVID

So do you think I am hurting my beer by adding AA during the mash?

 

[JockyBrewer]

I didn't realise, and I've never heard it mentioned before, that using crystal malts promotes oxidation in the packaged product. My experience with bottled bitters is that they can taste alright to start with and then that "cloying sweetness" really can set in. Any comments on this, anybody?

Personally I would say that crystal malt tends to highlight oxidation rather than cause it. You end up with that caramel sweetness that becomes the dominant character of the beer, although at that point I would expect that if you had made the same beer without crystal malt that the hops aroma and flavour would have been oxidised away too by that point.

Crystal malts do have a shorter shelf life than other malts though, they go stale pretty fast when crushed.

 

[JockyBrewer]

I've seen this solution before and it looks really neat. Better than putting the hops in the hopper as they get more exposure to beer. Will give it a try when my AliExpress order arrives.

I've also added a circle of silicone sheet under the cap of the keg hopper as it stops hops getting sucked through the holes at the top. Could could instead add some fine mesh or a metal sheet.

 

[DocAnna]

I've never noticed any cloying sweetness with any beers that use crystal malts (of which a lot of British ales do).


I dug deep on this one. All I could find about Ascorbic's 'super-oxidiser' properties were just people on reddit/forums saying "they had heard it somewhere else" and just parroting the information. I also found that this might be true if the fermentation medium is low in sulphur (hence the need to add SMB). Wine must is naturally low in sulphur (where I think that this 'information' came from) but beer is not.
So as best I can find out, the promotion of oxidation/super-oxidiser properties of AA do not happen in beer and people have read about it in wine, and just started saying the same thing about beer.

I've written about some of this before. The 'super-oxidiser' description of AA is because it is a superoxidiser - of itself, not of other things. That seems to be where some of the confusion arises.
https://www.thehomebrewforum.co.uk/...are-they-mutually-exclusive.90186/post-957950https://www.thehomebrewforum.co.uk/...are-they-mutually-exclusive.90186/post-993291
The research referred to in the video about the difference between Ascorbic acid with or without sulphite is this....

Tomic, D., Grigorakis, S., Loupassaki, S. & Makris, D.P. 2017, "Implementation of kinetics and response surface methodology reveals contrasting effects of catechin and chlorogenic acid on the development of browning in wine model systems containing either ascorbic acid or sulphite", European Food Research and Technology = Zeitschrift für Lebensmittel-Untersuchung und -Forschung.A, vol. 243, no. 4, pp. 565-574.

It's a complex paper using an simplified model of wine - ie not wine, and looking at the production of brown pigments. It is super super specific and was only cited by 8 further papers, and none since 2018. In the paper, it talks about the long term browning effect after all the ascorbic acid has been consumed. This is not as far as I can see from reading it, relevant to beer.

Regarding kilned/caramel malts they are protective for oxidation not promoting it! The confusion seems to be that an antioxidant by definition oxidises itself to protect other things from oxidising. So darker malts contain more phenolic antioxidant materials that consume themselves in oxidation before undesired oxidation.

Samaras, T.S., Camburn, P.A., Chandra, S.X., Gordon, M.H. and Ames, J.M. (2005) ‘Antioxidant Properties of Kilned and Roasted Malts’, Journal of agricultural and food chemistry, 53(20), pp. 8068–8074. doi:10.1021/jf051410f.

 

[Agentgonzo]

So do you think I am hurting my beer by adding AA during the mash?

I don't think so. At worst, it'll just have no effect. But I defer enterely to @DocAnna as she understands the science way more than anyone else here I think!