Oxygenation of Wort
This article talks about how to use pure Oxygen to oxygenate your wort before pitching yeast.
SAFETY FIRST!
WORKING WITH PURE OXYGEN CAN BE DANGEROUS AS IT PRESENTS A FIRE RISK. ALWAYS WORK OUTSIDE. NEVER WORK NEAR ANY SOURCE OF IGNITION.
Introduction
So for oxygenation you need a source of oxygen, a regulator, a connector, ideally a flow meter, some 3/8” beer line tubing (or metal) and a sintered stone.
Roughly – 5 (US) gallon brew of normal strength beer takes 1l/min for 1 minute, twice as long for strong beers.
Oxygen Source and Regulator
There are two options for the source of oxygen:
- Oxyturbo disposable cylinders
- Larger refillable tanks
For both, the oxygen isn’t claimed as food grade, but it often comes from exactly the same tank as medical oxygen, it just isn’t tested. Some say it's worth fitting an inline filter just to catch any oil or particles etc.
Oxyturbo disposable cylinders
These are available in shops or online and can be posted by courier. They are single use. They are sold fairly widely (they are used for welding) and you can get them for about £20 if you buy a few at a time and shop around.
They are 1 litre capacity and 110bars, so about 110 litres of oxygen, in experience this is actually enough to oxygenate around 25-30 beers when dosing 1 litre of oxygen in each beer.
Mini regulators for these are £25 without a gauge or £35 with a gauge. It's worth buying the one with the gauge as it’ll tell you when you’re close to running out of oxygen and you can screw on a JG 3/8” BSP connector directly. The cheaper reg without a gauge has a barb that is too small to fit any tube to, but you can screw in a smaller John Guest fitting, but it might require cutting down which can make it leak.
- Plus – Easy to order, no deposit, small and compact.
- Negatives - Expensive for the volume of oxygen you get.
Refillable Cylinder
Available from welding suppliers, I got mine via Adams here https://www.adamsgas.co.uk/product-category/hobby-welding-gas/
So these cost £46 a refill. They are 10 litre 200 bar – the same as 18 disposable cylinders (for the price of 2 of them). However, you have to stump up a (refundable) deposit (maybe £55) and delivery (£12 – but if you're getting CO2 for your kegs anyway...)
A single stage regulator is sufficient and costs about £27.
The output is a 3/8 bsp thread so a simple JG connector to 3/8 line works nicely.
- Plus – works out cheaper over maybe 3-5 years, even if you write off the deposit.
- Negatives – takes up more room and heavy, higher initial outlay
Flow Meter
Seems optional, but you can easily end up dumping out a lot of expensive oxygen without one, and possibly even overdosing your yeast. Again there are options here:
- An Argon flow meter will screw straight into the 3/8 regulator thread so everything is neat and fixed to the regulator. Try and find one that has the right flow range (1-2 litres per minute), although most will cover 0-14 Litres per minute and cost about £20.
- Alternatively you can buy flowmeters on eBay that are 0-1.5 Litres per minute for around £10. They have barbs to take 3/8" beer/gas line.
Sintered Stone / Oxygenation Wand
A 0.5 micron sintered stone is normally what you'd use here, but it can be difficult to submerge if on the end of a flexible tube.
BrewBuilder have previously made an oxygenation wand that is a bit easier to use. https://www.brewbuilder.co.uk/air-stone-wand.html
Cleaning
Don't touch the stone with uncovered hands - the oils on your fingers will clog the tiny holes in it and stop it working.
The stone can be sterilised by boiling before use. Boil it in some hot citric acid straight after each use to ensure it doesn’t clog up with sugar from the wort or chalk in the water.
Personally (James) I boil it in citric acid after use and then wrap in cling film after cooling a bit. That way it stays sterile until I need it.
Tips for use
- It's easier with a conical to use a flexible beer line and feed it in through the centre port on the lid, but you can use a metal wand for buckets or small plastic vessels etc.
- Use the stiff gas line to connect everything - flexible PVC tubing kinks and narrows when moved around causing the flow rate to vary greatly.