We recommend an oxygen flow meter that reads up to 1. If using an oxygen regulator with built-in flow control it's best to use one meant for brewing as the flow rate adjustment range is tuned to allow finer control at the low end where we need it typically 1 litre per minute.

For example, the Blichmann oxygen flow regulator has presets for 0. Most industrial or medical oxygen regulators are designed for higher flow rates up to litres per minute and may have presets that are not as accurate at the low end.

When using pure oxygen position the 0. The goal is to minimize the amount of bubbles you see at the surface as that is wasted oxygen that hasn't been absorbed by the wort.

This method is difficult to implement with any consistency as the two flow rates pure oxygen and wort must be carefully controlled to avoid inconsistent oxygenation. We recommend instead that pure oxygen be added after the wort is in the fermenter as it is easier to control the level of dissolved oxygen. While pure oxygen can certainly be used for all beers, we only use it for ales with gravity above 1. For lower gravity ales we prefer the simpler agitating rod method of aeration.

Pure oxygen is highly flammable. Ensure you read and follow the safety precautions outlined in the documentation that was included with your oxygen tank and regulator. Different equipment, wort gravity, wort temperature, and even fermenter geometry means that dissolved oxygen levels are difficult to predict and can never be guaranteed.

Use a dissolved oxygen meter. Dissolved oxygen meters have historically been very expensive but over the years have come down enough in price such that serious homebrewers now use them to confirm their wort dissolved oxygen levels before pitching yeast.

We recommend the Milwaukee MW Using a meter allows the brewer to measure levels and adjust to remove inconsistencies from batch to batch.

The Milwaukee MW uses a polarographic probe no stirring or agitation is required and supports two-point manual calibration and automatic temperature compensation for greater accuracy.

The probe uses an oxygen-permeable polytetrafluroethylene PTFE membrane sensor that requires periodic replacement. When it becomes wrinkled or has stretch marks, it's time to replace it. See Milwaukee MA spare membrane. We suggest picking up an extra bottle of Milwaukee MA oxygen electrolyte solution used for calibration at the same time. Milwaukee MA oxygen electrolyte solution and MA spare membranes. An electronic book version of the main build instructions on our website perfect for reading offline, printing, or just having a backup.

Available for immediate download - no waiting! All rights reserved. Powered by Shopify. Menu 0. Introduction Recommended dissolved oxygen levels Parts and tools Fizz-X wort agitating rod Atmosphere based aeration system with pump and diffusion stone Pure oxygen based oxygenation system with tank and diffusion stone Milwaukee MW dissolved oxygen meter Introduction Buy Now.

View this post on Instagram. Buy Now. The Complete Guide to Building Your Brewery An electronic book version of the main build instructions on our website perfect for reading offline, printing, or just having a backup.

More Wine! Ale strains above 1. Pure oxygen at a rate of 1 litre per minute for seconds per 5 gallons. Most homebrewers understand this in a general way, but whereas many of us are willing to go to some trouble to control fermentation temperatures or use proper pitching rates, few of us seem willing to make the same effort to ensure that our yeast have enough oxygen to perform at their very best.

This is to some extent understandable. After all, traditional aeration methods such as shaking the fermentation vessel or spraying wort can be quite effective and usually result in decent beer.

But there are risks associated with these methods, especially in bigger beers. These risks include:. So how can we minimise these risks? The answer, short and simple, is to use pure oxygen, the most efficient and reliable method of oxygenation open to the adventurous home brewer.

The article below approaches this topic from two angles. The first section explains how to determine the ideal level of dissolved oxygen to help minimise the risks listed above. The second section explains how to put together an oxygenation system to dissolve pure oxygen into your wort in an accurate and predictable manner. Section one — determining your oxygen requirements. To determine the ideal level of dissolved oxygen in wort you need to work backwards as follows:.

In practice, the higher the yeast pitch rate, the more oxygen you will need to dissolve into solution. There are exceptions to this rule — for example, Belgian Trappist brewers sometimes deliberately underpitch to encourage increased ester formation for a more complex flavour profile — but we can ignore these cases for present purposes.

Suppose we want to brew a medium strength ale with a starting gravity of, say, 1. The screen shot below illustrates how you might calculate this figure yourself using the Mr Malty Yeast Pitch Calculator this calculator was created by Jamil Zainasheff, the co-author, alongside Chris White, of the book Yeast , from which I am taking most of the raw data for this article.

Ok, so now that we know that a 20 litre batch of medium strength ale requires roughly billion cells, how do we use this information to work out the ideal level of dissolved oxygen? White Labs have already done all the work for us, and according to their research, the minimum recommended level of dissolved oxygen for a medium strength ale is parts per million White, , p. To put this in perspective, it is interesting to consider the following table from the Wyeast Laboratories website , which records the effectiveness of various methods of aerating or oxygenating wort:.

You can see here that the most that can be dissolved into solution by using aeration as opposed to oxygenation is 8ppm. And this will only be achieved if you splash and shake a vessel very vigorously and using plenty of head space, or spend at least 5 minutes pumping air using an aquarium pump and stone.

But even if you take full advantage of these aeration methods, you will still only achieve a level of dissolved oxygen of 8ppm, the minimum required for a medium strength ale. To be on the safe side, we really should aim to dissolve at least 10ppm. In fact, certain yeast strains for example, some lager strains might require levels levels as high as ppm. And stronger worts say above 1. At this point, it might be helpful to lay out some simple guidelines:.

As we discussed earlier, the ideal level of dissolved oxygen in each case is determined by the yeast pitc h rate, which is a function, in turn, of the strength of the wort, or in the case of lager yeast strains, the need to pitch roughly double the cell count to compensate for the colder fermentation temperatures.

The porous stone creates thousands of very small bubbles. These small bubbles have a larger surface-to-volume ratio than bigger bubbles, allowing more oxygen to be absorbed on the way to the surface. It just depends on how much you want to DIY. This goes for whatever system you use, whether you buy one or build it, sanitation is incredibly important.

Note: This method is easier than agitation, but still can only put the wort in the lower 8 ppm range. In this method a pressurized gas cylinder replaces the aquarium pump and you feed your wort pure oxygen. Much higher dissolved oxygen levels can be achieved.

This becomes especially important when brewing high gravity beer. Generally about 60 to seconds will get you in or above the 8 to 10 ppm range. Gauging flow can be done, to some extent, by watching the bubbles. As flow increases more and more of the small bubbles will combine making bigger bubbles and more of these bubbles make it to the surface. Now, as mentioned earlier smaller bubbles have a larger surface-to-volume ratio then do larger bubbles, so it stands to reason to have smaller bubbles.

Also, the more agitated the surface, the more oxygen is escaping and going unused. Find a flow that gives you the most amount of small bubbles with the least amount of churning at the surface. Also, over oxygenation becomes a concern with this method. At this point, if there is oxygen left in the environment the yeast use it to create more flavor compounds, which can equate to flavor problems.

The excellent book Fermentation, Cellaring, and Packaging Operations edited by Karl Ockert gives the detrimental amount at more than 40 ppm. Note: You lose head forming compounds through excessive foaming. So, oxygenating or pump aerating too long and too vigorously will likely result in a finished beer with very little head or head retention. This was the idea presented in an experiment done by Grady Hall at New Belgium Brewing Company as part of his postgrad work.

The experiment is quite interesting and Mr. In short the experiment tested whether olive oil, a rich source of oleic acid a precursor of UFAs , could be added in place of aeration.

All four experimental batches fermented slower than the aerated controls. The batch dosed with the most olive oil, still minuscule at 1 milligram per 25 billion yeast cells, had a fermentation time of 94 hours as compared to the 83 hour fermentation of the control. All fermentations reached terminal gravity which seemed to speak to good levels of UFAs.

A follow up tasting panel found that after the beer had been aged warm for three weeks oxidation was less noticeable in the experimental beer.

New Belgium found the results were similar enough to the Fat Tire standard that they packaged and sold the beer. Maybe you drank one. Well, first we have to understand that our homebrew is hopefully treated better than most commercial beer.

So, how stable you want your beer really depends on your batch size and how long it takes you to drink it all up. But if you do want to try this approach there are a couple things to think about. So, as Mr. Hall suggests at the end of the paper experimentation would have to be done with adding some form of sterol or aeration, plus the olive oil. The one place this might be pretty pertinent for the homebrewer is when brewing high gravity beers. The possibility of using olive oil in conjunction with aeration could eliminate the need for oxygenation, or at the very least cut down on oxygenation times.

Second, is the amount of olive oil. The amount used in the experiments is very small, bringing it down to a homebrewing level makes in infinitesimal. But, looking around on different forums, some brewers have gotten decent results by sticking the tip of a toothpick or other small instrument into the olive oil, then stirring it into the yeast starter.