I used to tip from fermentor to fermentor once I,d cooled the wort and until the foam was too much to handle, I got pretty good results but ended up with spilt wort on many occasions and a bad back from lifting 28 litres of wort,
My $30 aerator with inline spraypainting paper/carbon filter has been much easier, I can continue to aerate for a number of hours after pitching once the foam settles and all in all Ive had better results, faster ferments, higher attenuation, and quicker to start.
Wort Aeration
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Bru4u
There was an artical in Brew a few months ago on using pure oxygen, some lad asked was welding O2 ok to use and the answer is below.
Hope you find it helpful
The short answer to your question is that welding grade oxygen is probably OK for homebrewing. I know that the only difference between medical grade and welding grade oxygen at my local industrial gas supply is the container the gas goes in. Medical grade oxygen must go into containers that are only used for that grade and there are probably some special inspections and filling procedures used for the medical grade stuff. The actual oxygen gas comes from the same bulk tank. My guess is that most gas suppliers use a similar procedure. As far as contaminants from oxygen go, microorganisms are not a concern because, as you mention in your question, pure oxygen is not a very hospitable environment.
I do suggest using caution when using pure oxygen to oxygenate wort. The problem you face is that the solubility of oxygen in wort is much higher when pure oxygen is used instead of air. Most brewing texts cite the ideal level of oxygen in wort prior to fermentation at around 8 ppm or 8 mg/L. Levels higher than this can cause oxidative damage to yeast cells. When using pure oxygen, wort oxygen levels of about 30 ppm are possible, making over-aerating a legitimate concern. One way to meter the flow of oxygen into wort is to use a gas flow meter. Gas rotameters are common and relatively inexpensive devices that measure the
flow of gas.
If you have a flow meter, you can use it to meter gas flow and determine the amount of gas required given a few assumptions. Let’s say you want to add 8 mg/L of oxygen to your 20-liter batch, you can see that you will need 160 mg of oxygen (Note to metricphobes: get over it! The metric system is so much easier than our units when doing these types of calculations. No metric to English conversion is offered because chemistry simply cannot be addressed without using the metric system). 160 mg is equivalent to 0.005 moles of oxygen (0.16 grams/32 grams of oxygen per mole = 0.005 moles). If you multiply 0.005 moles by 22.4 l/mole you see that 0.112 liters of oxygen are required to supply the 160 mg required to yield a concentration of 8 ppm in your 20 liters of wort.
I said there are a few assumptions required for this calculation. The first assumption is that all of the oxygen injected in the wort goes into solution. This is not a bad assumption if the oxygen is bubbled from the bottom of the fermenter and the bubbles are really small. A wand with drilled holes (rather than a gas stone) would produce larger gas bubbles which have a reduced tendency to dissolve into the wort. This would be evident as bubbles break the surface of the wort. Assuming 100% transfer is not a bad assumption as long as you use a stone and keep the oxygen flow slow during aeration. The second assumption is that the ideal gas law is valid enough for brewing and that one mole of oxygen is similar enough to an ideal gas that the 22.4 liters/mole (at atmospheric pressure) conversion is believable. In my opinion, the ideal gas law is certainly good enough for brewing. If you are a chemistry guru fell free to use your favorite equation of state.
If you want to buy a gas rotameter look for one that is scaled in liters per minutes (not cubic feet per minute) with a range between 0-1 Liter/minute (lpm) and 0.1 subdivisions. In this example, running the gas flow at 0.2 liters per minute for 30 seconds will introduce about 0.1 liters of oxygen.
Some brewers attempt to replace a gas flow meter with a gas pressure gauge. Without getting into details, I do not recommend using pressure as an indication of flow because it simply does not work well. Unless you know that 10 psi gas pressure delivered to your stone gives some known flow rate you are guessing. The bottom line is that to use oxygen for brewing you really should have a flow meter.
Once you get some experience in introducing oxygen into your wort you can begin making adjustments. If you believe that less than 100% of the gas is going into solution, you can make small adjustments to compensate for the loss. Without measuring the oxygen concentration in your wort this is certainly a guess, but it can be a reasonable one. If you approximate that you are getting 90% of the oxygen injected into your wort, simply divide 0.112 by 0.90 and increase the oxygen volume to 0.124 liters. By using a flow meter you can make small changes with the confidence that accompanies knowing your flow.
We use air for aeration at Springfield Brewing Company. Dry compressed air comes into our aeration panel, flows through a sterile filter, then to a rotameter flow meter before the in-line injection point. Whether using oxygen or air, gas flow meters are handy gizmos to have around the brewery!
Hope you find it helpful
The short answer to your question is that welding grade oxygen is probably OK for homebrewing. I know that the only difference between medical grade and welding grade oxygen at my local industrial gas supply is the container the gas goes in. Medical grade oxygen must go into containers that are only used for that grade and there are probably some special inspections and filling procedures used for the medical grade stuff. The actual oxygen gas comes from the same bulk tank. My guess is that most gas suppliers use a similar procedure. As far as contaminants from oxygen go, microorganisms are not a concern because, as you mention in your question, pure oxygen is not a very hospitable environment.
I do suggest using caution when using pure oxygen to oxygenate wort. The problem you face is that the solubility of oxygen in wort is much higher when pure oxygen is used instead of air. Most brewing texts cite the ideal level of oxygen in wort prior to fermentation at around 8 ppm or 8 mg/L. Levels higher than this can cause oxidative damage to yeast cells. When using pure oxygen, wort oxygen levels of about 30 ppm are possible, making over-aerating a legitimate concern. One way to meter the flow of oxygen into wort is to use a gas flow meter. Gas rotameters are common and relatively inexpensive devices that measure the
flow of gas.
If you have a flow meter, you can use it to meter gas flow and determine the amount of gas required given a few assumptions. Let’s say you want to add 8 mg/L of oxygen to your 20-liter batch, you can see that you will need 160 mg of oxygen (Note to metricphobes: get over it! The metric system is so much easier than our units when doing these types of calculations. No metric to English conversion is offered because chemistry simply cannot be addressed without using the metric system). 160 mg is equivalent to 0.005 moles of oxygen (0.16 grams/32 grams of oxygen per mole = 0.005 moles). If you multiply 0.005 moles by 22.4 l/mole you see that 0.112 liters of oxygen are required to supply the 160 mg required to yield a concentration of 8 ppm in your 20 liters of wort.
I said there are a few assumptions required for this calculation. The first assumption is that all of the oxygen injected in the wort goes into solution. This is not a bad assumption if the oxygen is bubbled from the bottom of the fermenter and the bubbles are really small. A wand with drilled holes (rather than a gas stone) would produce larger gas bubbles which have a reduced tendency to dissolve into the wort. This would be evident as bubbles break the surface of the wort. Assuming 100% transfer is not a bad assumption as long as you use a stone and keep the oxygen flow slow during aeration. The second assumption is that the ideal gas law is valid enough for brewing and that one mole of oxygen is similar enough to an ideal gas that the 22.4 liters/mole (at atmospheric pressure) conversion is believable. In my opinion, the ideal gas law is certainly good enough for brewing. If you are a chemistry guru fell free to use your favorite equation of state.
If you want to buy a gas rotameter look for one that is scaled in liters per minutes (not cubic feet per minute) with a range between 0-1 Liter/minute (lpm) and 0.1 subdivisions. In this example, running the gas flow at 0.2 liters per minute for 30 seconds will introduce about 0.1 liters of oxygen.
Some brewers attempt to replace a gas flow meter with a gas pressure gauge. Without getting into details, I do not recommend using pressure as an indication of flow because it simply does not work well. Unless you know that 10 psi gas pressure delivered to your stone gives some known flow rate you are guessing. The bottom line is that to use oxygen for brewing you really should have a flow meter.
Once you get some experience in introducing oxygen into your wort you can begin making adjustments. If you believe that less than 100% of the gas is going into solution, you can make small adjustments to compensate for the loss. Without measuring the oxygen concentration in your wort this is certainly a guess, but it can be a reasonable one. If you approximate that you are getting 90% of the oxygen injected into your wort, simply divide 0.112 by 0.90 and increase the oxygen volume to 0.124 liters. By using a flow meter you can make small changes with the confidence that accompanies knowing your flow.
We use air for aeration at Springfield Brewing Company. Dry compressed air comes into our aeration panel, flows through a sterile filter, then to a rotameter flow meter before the in-line injection point. Whether using oxygen or air, gas flow meters are handy gizmos to have around the brewery!
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Aleman
- It's definitely Lock In Time
- Posts: 6132
- Joined: Sun Jun 03, 2007 11:56 am
- Location: Mashing In Blackpool, Lancashire, UK
Thats not a bad article, although I question some of the assumptionsBru4u wrote:There was an artical in Brew a few months ago on using pure oxygen, some lad asked was welding O2 ok to use and the answer is below.
The interesting fact is that welding grade Oxygen (O2) is actually less contaminated than medical grade . . . . The contaminants in medical grade would weaken any weld . . . . . Although having said that medical grade is >99.5% pure O2-
adm
-
Aleman
- It's definitely Lock In Time
- Posts: 6132
- Joined: Sun Jun 03, 2007 11:56 am
- Location: Mashing In Blackpool, Lancashire, UK
It's not far fetched, the idea is that you are providing the yeast with raw Unsaturated Fatty Acids (UFA) which it uses to build cell walls. It can derive the UFA's from sterols and ergosterols (from lipids in wort, and cold break in trub), but this takes energy to do so, so its more efficient to utilise the UFA's directly . . . . . My issue is not with the idea, its the quoted quantities of 'oil' required to produce the effect. While olive oil has high levels of UFA's this is in relation to other oils, so while it may have 100 times the UFA concentration of lard (random example to illustrate a point) if the actual level of UFA's in olive oil is only 0.01 mg/ml. The research I've done so far seems to show that adding UFA's directly to the wort works well, adding oil may not be anywhere near as effective as claimed. So far in the brewing environment I've not seen any quotes that show measured levels of UFA / Oxygen concentration throughout the fermentation, most seem to be in small level lab brews (up to 1L ) rather than a batch. I've also seen figures quoting as much as 150ml of olive oil could be required to achieve decent yeast growth in 5Gallons of wort.adm wrote:Has anybody tried the "Olive Oil" technique? Seems to be getting popular over the pond....
Dip a toothpick in Olive Oil, then rinse it in the yeast started or cooled wort..
Sound far fetched. Anybody know?
I may try it in a starter, but it will be a belt and braces approach in addition to my usual aeration and stir plate approach . . . I now lack the lab facilities to do a proper analysis.