Wort is down and cooling in the cubes. I went with No-chill, as I ran out of time and... well.... I didn't want to be up to midnight cleaning my equipment. Again!! I will cool to fermenting temps tomorrow, while I'm at work and in the evening give the H2O2 experiment a go. I wasn't able to get the 6% solution as they were out of stock, but I got 3% Gold Cross, so will give it a crack with that. Full recipe and method to follow, when some preliminary results are in. Till then...
Get into O2 guys, if you're serious about nicer beer
Posted 09 March 2017 - 05:28 PM
Okay, so preliminary results are in for H2O2 v Aeration (standard shake till you can shake no more) comparison experiment in temp controlled conditions at full batch volume.
The fermentation is almost complete (in yeast clean up mode now) and I will say the comparison experiment is a success, as it has achieved one result for a hypothesis I was looking to test. In short I can say that I don't believe that H2O2 adds a benefit to fermentation in the same way as O2 is reported to do.* The fermentation was NOT quicker than standard shaking aeration. It was NOT more complete with better attenuation and quicker brightening (clearing). The H2O2 batch did not do terribly, but it was by no means better than standard aeration. In fact H2O2 achieved just under in attenuation (72% v 78% so far at day 9) and produced more esters at the same temperature.
I've attached my full recipe notes below,** but have summarised some of what I think are the key points here.
- Brews fermented with exact same yeast manufactured on exact same date bought cold and stored cold. Yeast calculators showed the viability to be 66% on the day of pitching but I think that is a massively conservative number (read - bunch of rubbish) as the results indicate otherwise so far.
- H2O2 batch was 1 litre more than Aerated batch.
- H2O2 batch had no splashing of any kind to minimise any variable of added O2 by other means. Aerated batch was splashed and shaken till I could do no more (3 min shake, I know I'm pathetically out of shape
- Temp control probe attached to outside wall of H2O2 fermenter, meaning the Aerated batch could have been a bee's appendage higher or lower, but not much of a variable.
- Both fermentations appeared to begin around the same time (first noticed activity in both at 19 hours post pitch) and both appeared to behave the same up until first gravity reading (5 days).
- At 5 days, the H2O2 batch had much more yeast in suspension and was 2 gravity points higher than the Aerated batch. The H2O2 batch had much stronger flavours and aromas that the Aerated batch, which together with the very cloudy suspended yeast appearance and the slightly higher gravity is likely an indicator of yeast stress. The H2O2 batch sample had a very dry to puckering after taste that I thought did not bode well for it.
- At 9 days, the H2O2 batch had the same amount of very cloudy yeast in suspension, and was 3 gravity points higher than the Aerated batch, but both had gone lower than the predicted FG of 1015. The H2O2 batch sample taste and aroma were again much stronger than the Aerated batch, but both had cleared most of their green beer flavours and the H2O2 batch had lost the puckering after taste.
So in conclusion, I can't say that the H2O2 has ruined the fermentation stage or killed off all the yeast, but it is indicative that the H2O2 batch has attenuated lower (I know it's slight) and produced a yeast that seems to be under stress (especially as this is a highly flocculant variety).
Further updates will take place as planned with the testing for oxidation of the final product over the next months.
Vienna H2O2 experiment 26 02 17.docx 23.08KB 6 downloads
DSC_2808.JPG 188.08KB 18 downloads
Brewery set up at Mash stage to show I have no fancy set up (all gravity set up)
DSC_2810.JPG 287.3KB 18 downloads
Yeast blow out prior to second clean up at 56 hours
DSC_2812.JPG 77.52KB 20 downloads
EDIT - * I say reported as I have never used O2 in brewing.
** Notes only complete up until today
Edited by Jack of all biers, 09 March 2017 - 05:33 PM.
Posted 09 March 2017 - 09:54 PM
Thank you very much for that report.
I have just today kegged (and bottled) the results of my side-by-side comparison. I did one batch with 10mL of 6% H2O2 and one batch with about 5 minutes of drill+paint stirrer aeration.
Both the fermentation process and the resulting aroma/flavour at bottling time were the same. Both batches ended up at the same FG and as far as I can tell got there at either the same time or within 24 hours of each other. I also observed that the H2O2 sample was cloudier than the aerated sample. The H2O2 sample seems to have slightly better head retention and lacing on the glass.
Based on this side-by-side comparison, I would conclude that there is no clearly visible benefit to using H2O2 vs vigorous aeration. I also don't think there is a detriment.
The only differences I could see (turbidity, lacing and head retention) can possibly be explained by the mechanical aspect of aeration, rather than the O2 content in the wort.
Not exactly the same results as yours, but the conclusion seems similar - H2O2 is not a silver bullet. Unfortunately I have no pure O2 experience to compare against. From all the comments in the forums, pure O2 gas should deliver a clear difference.
Posted 10 March 2017 - 04:54 PM
For another experiment you might like to compare H2O2 to no aeration. If you don't have O2 and can't be bothered to aerate is H2O2 an easy replacement for vigorous shaking?
Not going to prove anything in my opinion. Which is based on my suspicion that H2O2 did not produce much O2 to begin with in my test. It would be good if anyone who had an O2 meter did a couple of mini batches using H2O2 to test how much O2 is convert when added to wort plus yeast. Then someone who had the expertise to determine how much, if any yeast mutation occurs. With my results so far I can GUESS these, but can only say for sure that it seems similar to a barely aerated batch that I once did. I forgot to shake, but was poured from a minimum height (barely aerated). This one also struggled and had yeast hanging about in suspension for a long time (different yeast)