peteru said:
O2 aeration is good, but if you are doing kits there is a very easy, safe and cheap way of getting good amounts of O2 into the fermenter.
I have a 15L cube that I fill with filtered water and a small amount of hydrogen peroxide. Chill the cube overnight. When doing kits or partial boil with extract, use this cold oxygenated water to top up the fermenter once to concentrated wort has been dissolved.
Hydrogen peroxide only costs about $4 for 100ml from the local chemist, which is enough for about 5-10 batches. Bigger bottles and higher concentrations are also available, if you want to reduce the cost even further.
Peteru, your post got me wondering on the whole adding O2 via H2O2 method and whether it could be employed on AG brewing also. Potentially adding a calculated amount of H2O2 to cooled wort (less than 25C) in the FV to oxygenate it prior to adding the yeast starter. I'm guessing it would take more time that O2 gas addition, but would be a lot cheaper in initial outlay and ongoing cost.
MHB said:
If all of the H2O2 breaks down into H2O and O2 (2H2O2 > 2H2O + O2) the yield is close to 50%, so your yield of O2 would be 0.6g
A bit of a surprise, but it looks like there is plenty of O2 available.
The only question being, is it breaking down or are you still getting most of it going into the brew as peroxide that will damage yeast, I suspect the answer is a bit of a mixture, but from your observations a fair fraction appears to be breaking down and going into the brew.
Have to give this a bit more thought.
Especially once MHB had done the numbers, although having done a little internet research, I'm not sure even 50% of the H2O2 would break down overnight in your water as the decomposition of H2O2 is quite variable. I'm thinking that once it is added to the wort then the speed of decomposition into H2O and O2 would greatly increase. Once yeast is added this would increase the rate again, as per Adro's link (if any H2O2 were even left after contact with the wort). So once the H2O2 solution is added to the wort the O2 level should theoretically increase. Right?
Bribie G said:
Fauldings brand 3% Hydrogen Peroxide at around $4.50 for 200ml
I always have a couple of bottles around, mostly for treating ingrowing toenails. Might give it a go with my next brew.
hydrogen peroxide.JPG
My only counter thought is that normally H2O2 (as linked by Bribie above) has stabilizers added to keep the H2O2 from decomposing in the container before you the consumer use it. A quick internet search reveals a lot of scare mongering out there about such stabilizers, but no proof or links to research. That being said, most producers are not producing H2O2 solutions for ingestion by humans, so it is hard to know the health implications of consuming said stabilizers (drunk by the end user of the beer, as opposed to a mouth wash that is spat out again).
H2O2 is sold without stabilizers (sold as "Food grade" Hydrogen peroxide), but I'd wonder about the percentage (35%) they claim and how long it would last in its packaging without the stabilizers added (H2O2 is more stable in cold and acidic conditions). Also the stabilizer free H2O2 is sold at rates like $13 per 236 ml of 3% solution online which is a fair bit more expensive than the pharmacy bought one at $4 to $5.
Don't get me wrong, I am very interested by the use of H2O2 to oxygenate the wort (so much so that I'd like to try it), but am wondering if there is more info/knowledge out there about about the different reactions (positive and negative) between the different stabilizer additives with the wort and any by-products/effects on the fermentation/end product. Adding chemicals to wort that I don't know anything about keeps me from trying this one until someone can point me in the right direction. So with that in mind can someone who has a better mind for chemistry look at the below info I found at this site www.h2o2.com/faqs/FaqDetail.aspx?fId=11 and tell us if any of those stabilizers are a potential issue?
"Most commercial grades of H2O2 contain chelants and sequestrants which minimize its decomposition under normal storage and handling conditions.
The types of stabilizers used in H2O2 vary between producers and product grades. Common stabilizers include:
- Colloidal stannate and sodium pyrophosphate (present at 25 - 250 mg/L) are traditional mainstays.
- Organophosphonates (e.g., Monsanto's Dequest products) are increasingly common.
- Nitrate (for pH adjustment and corrosion inhibition) and phosphoric acid (for pH adjustment) also are used.
- Colloidal silicate is used to sequester metals and thereby minimize H2O2 decomposition in certain applications that depend on the bleaching ability of H2O2 in alkali.
In some applications, a high degree of stabilization is needed; whereas, in others (e.g., drinking water treatment or semiconductor manufacture) product purity is more important. For most environmental applications, H2O2 stabilization does not affect product performance."