I have been offered an oxygen cylinder that's supposed to be used for welding (as opposed to medical grade oxygen). Is it safe to use this for oxygenating wort? If I open the cylinder to push away dust before attaching a regulator and clean all the threads, would this be enough to minimize the risks?
Haha, the thought had crossed my mind :)
And to think this gas could have ruined the "DUBLINERS" as a great folk group. :P
Last time I was looking at industrial grade oxygen was back in the 80s. I seem to recall that this is just denitrogenised-air rather than pure oxygen. As such it is 90% to 93% pure.
When brewing, most people use the swirl and splash technique to perform oxygenation where atmospheric air is the active ingredient. Since industrial oxygen is this same air with the nitrogen removed, you should see nothing harmful going on what so ever. Just be sure to filter it well before it enters the wort. Possibly bubble it through some sanitizer after the filter will also ensure your wort is well protected.
I would also suggest listening to Better Brewing Radio Episode Aug7, 2008. here (http://www.basicbrewing.com/index.php?page=basic-brewing-radio-2008). This episode is a comparison of the results of experiments in aeration using various pumping and shaking options. The PDF of the test can be had at here (http://media.libsyn.com/media/basicbrewing/AerationMethods.pdf). Bottom line is that swirl and splash is the best way to aerate wort.
/J
QuoteBottom line is that swirl and splash is the best way to aerate wort.
/J
Take THAT doctor. This oxygen obsession of yours has to stop. splish splash is all you need. 8-)
Industrial grade is pretty much the only way to go unless you go with expensive disposable oxygen tanks because no one will refill the medical grade tanks.
The medical tanks have a more sensitive regulator (which is nice) but you can't get them refilled; supposedly they're also glass-lined so you don't ever have to worry about rust but if the tank is aluminum you also don't have to worry about rust. An inline filter is still recommended.
Adam
Thanks Adam. I've done a good bit of research at this stage and I've found a couple of places that sell non-refillable cylinders with food grade oxygen at reasonable prices (well, reasonable by standards in the welding world). The problem with most suppliers of industrial grade oxygen in Ireland is that they charge rental on the cylinders, which pushes the cost way up to prohibitive levels. BOC and Air Products are the chief culprits. There are non-rental options available though, including Hobby Weld and Wholesale Welding Supplies, but they aren't cheap. The best set-up I've seen is from a scientific lab supply company. They sell 34L non-refillable cylinders (which would do roughly 34 batches assuming a flow rate of 1 litre/minute (which is the recommended rate in Chris White's yeast book). They also sell a fixed flow regulator set at .5 litres/minute, which would require roughly 120 seconds of oxygenation per batch. Again, it's not cheap to get set-up, but once you have the equipment in place you'd only need to replace your oxygen cylinder once ever 2 and a half years or so (assuming you brew once a month).
I'll probably do up a proper post on all this at some stage for anyone interested in using oxygen.
Justin, thanks for your post. I was already aware of that paper as it happens. However, they limit themselves to discussing aeration, not oxygenation. It's true that shaking is the most efficient way to aerate wort, but it has an upper effective limit which falls below the ideal level recommended by White Labs and Wyeast. Only oxygenation can get you to the ideal levels (roughly 10ppm - 14ppm).
Dr J, Can you PM me the link?
I also must get down to do a bit of research into using H2O2 or W5 Percarbonate as a source of O2.