Oxygenation

Liquid Bread^®, a leading innovator in home brewing techniques, was the first to introduce a system specifically for home brewers to effectively add oxygen to beer wort in preparation for fermentation. The Oxynater^™ is a complete system for increasing the level of oxygen in your wort prior to fermentation. Developed by home brewers who understand the needs of the home brewer, Liquid Bread^® offers a significant big brewery technique for your use.

During a Liquid Bread^® experiment, a beer was brewed and divided into two fermenters. One fermenter was shaken for an extended period in order to aerate the wort. The other was oxygenated using the Oxynater.

Into each fermenter the same quantity of the same liquid yeast was pitched. The Oxygenated wort began fermentation more quickly and appeared to be more vigorous. In fact, it was so much more vigorous that after only four days, the specific gravity of the oxygenated wort was 1.012 while the shaken aerated wort was still 1.024!

The end result was that the oxygenated beer was finished more quickly and better attenuated (drier and crisper). Of course, since home brewing is an art form, your mileage may vary.

So, when making your next brew, don’t settle for anything less than the original Liquid Bread^® Oxynater^™. Read on to find out why this product can be so incredibly effective.

The Need for Oxygen

Depending on your level of brewing skill, the need for oxygen in beer may or may not be understood. While most beginning brewers understand the basics of brewing, the details of the brewing process are typically learned as the brewer gains experience. As brewers mature, they begin to realize that, in addition to the ingredients used, improving home brewed beer is a function of understanding and improving the process used to make the beer. However, even after a brewer gains experience, it is very possible that the fermentation process and the need for oxygen still remains a mystery.

Beer and Fermentation

• Without fermentation we would have no beer, but only beer wort which is sickly sweet, sticky and for most consumers, pretty lousy to drink. If you’ve never tasted unfermented beer wort, try some and you will understand why fermentation is needed. In fact, we recommend that all brewers taste their worts in an effort to better understand beer flavors and the entire brewing process.
• Fermentation is the critical process in which millions of healthy yeast cells convert the sugars in beer wort into alcohol and carbon dioxide. It is also the process during which certain flavors known as Esters, which make beer taste like beer, are produced. Care must be exercised at this stage or other "off" flavors that have no place in beer can also develop.
• Fermentation is generally considered to consist of three distinct steps as follows:
  1. Respiration
     
  2. Reproduction
     
  3. Sedimentation
• Each step is critically important to the finished beer and with well fed, healthy and vigorous yeast, fermentation and sedimentation are typically never a problem. Yeast will usually work exactly as they are supposed to - assuming they are given the opportunity which you, the brewer, can provide through proper care and feeding. For more information on yeast, check out our links.

Care and Feeding of Your Yeast

Prior to starting respiration, the yeast prepare themselves by taking in nutrients from the wort. Once ready, the yeast begin the respiration phase by taking in oxygen. And lots of it. As much as is available in your wort. With one or two exceptions, you can’t put too much oxygen in your wort. This is an important point in the brewing process where you provide opportunity for your yeast through feeding. In fact, this is not even a case of equal opportunity, but unfair, unequal opportunity for your yeast. Read on!

• This raises a number of important questions including?
• Why oxygen is needed in beer wort?
• How oxygen is added to wort?
• Will it take longer to make beer if Oxygen is added?
• Can too much Oxygen be added to wort?

Why oxygen is needed in beer wort?

Not only is it important to have oxygen, but it is important that there be enough. Just like you need oxygen to live, without enough oxygen, you would not be able to run a marathon and you would fall far short of the finish. Yeast are no different. While better than no oxygen at all, inadequate oxygen for your precious yeast will be bad for your finished beer. The yeast may not be able to finish the marathon, or may have problems along the way. Here’s why.

Before the yeast can begin to turn sugar in your beer into alcohol and other beer flavors, they must first go through the respiration and reproduction phases to multiply from a few yeast cells to millions of yeast cells. This process requires lots of oxygen. Without oxygen, the yeast will not ferment at all. Instead, bacteria will take over and bacteria really don’t have a clue as to how to ferment beer wort! Since the boiling process forces all the oxygen out of the beer it must be added back before the yeast can perform fermentation. If you don’t remove the trub from your beer before fermentation, making sure there is plenty of oxygen for the yeast is a must. Yeast can and may use trub as a substitute for oxygen. According to Dr. George Fix, yeast metabolism stimulated by trub rather than oxygen can have detrimental affects on beer. Trub can also add to the production of nasty tasting fusel alcohols. Making sure you have plenty of oxygen will minimize the effect of trub. If possible, we recomend you remove the trub before pitching your yeast. This will provide your yeast with the best environment to make them as healthy as possible. When you can't or don't want to remove the trub, be sure to add plenty of oxygen.

During respiration, a number of reactions take place in the wort as it begins the transformation into beer. To understand the details of these reactions requires a PhD in biology and chemistry. However some enzymes used in the fermentation process are affected by the oxygen content in the wort. If oxygen is inadequate, then the enzymes may be as well. If there are inadequate enzymes, such as NAD+, the metabolic activities of the yeast won’t function properly and will produce excessive glycerol which can exceed flavor thresholds. In other words, your finished and prized beer, on which you spent numerous hours and tens of dollars will taste lousy, be spit out in competition and be used as fertilizer. This problem is a strong possibility in weakly oxygenated worts and in worts of high gravity.

High gravity worts, which are very heavy and thick, need more oxygen due to the higher levels of fermentable sugars they contain. In addition, Oxygen is not as soluble in higher gravity worts making them more difficult to oxygenate (add oxygen). In such cases, you could shake your carboy indefinitely (aeration) and never get enough oxygen in the wort. Some of the more creative brewers have used aquarium pumps running for one to two hours to aerate (oxygenate) their wort. Compare this to 30 to 45 seconds for the Oxynater^™! If oxygen levels in your wort are too low, a number of off flavors can be produced due to increases in the level of:

• Fusel Alcohols
• Fatty Acids
• Esters (those apple, banana, raisin, grape and many other fine flavors)

While many ales are supposed to have esters, it is possible that too much of a good thing can become bad. Although I do recall a wonderful banana brown ale that....Oops!

According to Greg Noonan's book "Brewing Lager Beer", yeast require a significant amount of oxygen during respiration ranging from 4 to 14 parts per million. With inadequate oxygen, yeast may autolyze (feed on themselves) producing a yeasty off flavor in the beer.

Fermentation may be slow and may stop (stuck fermentation) if there was too little oxygen in the wort. Once the fermentation process is started, it is too late. Oxygen should not be added after yeast have completed their respiration phase and have started fermentation since you run the risk of oxidizing your beer and increasing off flavors. It is best to be sure you get adequate oxygen in the beer in the first place. If you have ever entered a competition with a beer that did not ferment properly due to low oxygen level at the start of fermentation, you might have received comments from the judges such as sweet, sugary, cloying, unattenuated, lacks a clean crisp flavor. If you have these words on your score sheet, you need more oxygen!

Noonan also points out that yeast growth in beer can be limited by two factors. Inadequate amino acids or inadequate oxygen, but usually oxygen. This tends to indicate that, as a general rule, most brewers do not add enough oxygen to their beer wort, increasing the chances of a less than perfect beer. Are you one of those brewers depriving your yeast of oxygen?

Do you want to drink better beer? Then get yourself an Oxynater^™ and make a step change in your home brewing technology!

Unequal opportunity for your yeast. With too little oxygen in the wort, lag times ( the time it takes to start fermentation) are increased. This is bad for your beer and bad for your friends who have to drink your beer. Beer wort is an excellent growing medium for yeast. However, this means it is also a great growing medium for other organisms such as Lactobacillus and Pediococcus bacteria. A short lag time allows the yeast to become fully established, decreases the chance for infections and results in an improved final product. Long lag times may indicate a waste of your time and money. Reducing the risk of infection in home brewed beer was one of the primary reasons Liquid Bread^® created the Oxynater^™.

Exceptions

For advanced brewers fine tuning recipes that require significant Ester production, limiting the oxygen may help in the process. However, using oxygen and a known delivery system can aid in "dialing" in your recipe for the right amount of Esters. An example may be a Belgian Ale in which a high degree of esters is desired

How Oxygen Is Added To Wort

By adding sufficient oxygen to your wort BEFORE you add the yeast, you will give your yeast the opportunity to grow into a healthy colony capable of fully and properly fermenting your beer. The two basic approaches for adding oxygen are aeration and oxygenation. However, there are a number a ways to apply these techniques. A few of these are described below. Keep in mind that adding air or oxygen should be done preferably before, or soon after, adding the yeast!

Shake It Up

Aeration is achieved by mixing air into the wort. One method is to shake wort in a container with lots of air in it. This is typically done by most brewers using 5 gallon carboys. Please remember to stick a cork in it before shaking! The problem with this technique is that a full carboy does not contain a large enough volume of air. In fact, you may have no air at all. Because of a lack of air space or "head space" (to be technical) in the carboy, many home brewers shake the carboy when it is about half full and then continue to fill it up. The problem with this approach is that the last 2 or 3 gallons of wort go in without any air. Furthermore, air only contains about 21% oxygen. Finally, shaking is not all that efficient for adding air or oxygen. The end result is a wort without enough oxygen to promote the healthy growth of yeast. As many of you know from experience, shaking a carboy is hard work and may be difficult for those that don’t bench press 200 pounds. This can also be a dangerous practice in that the carboy could break, although the beer, splashing to the floor and splattering all over your walls, will be sufficiently aerated. Ask around and you will find a brewer that has dropped or broken a carboy during aeration.

Spray It

Another method of aeration is to spray the wort from the siphon tube as much as possible when filling your carboy or fermentation container. While this works, its effectiveness must be questioned. Also, once a carboy starts to fill, it becomes more difficult to spray the wort around.

Stir It

Vigorously stirring your wort can help, but, stirring in a carboy can be difficult if not impossible. In a fermentation bucket, stirring is possible, but is still likely to be less than effective and can also be messy.

Pump It Up!

Another method for aeration used by more inventive home brewers is to stick a hose into the wort connected to an aquarium pump. This may be better and safer than shaking a carboy, but is still raises the question of effectiveness. A diffusion stone added to the hose and pump may help, but now the pump may not produce enough pressure to aerate the wort. Also, who knows what else the pump may put in your wort with your yeast. Always remember, Lactobacillus is not your friend.

Oxygenation

As opposed to aeration, Oxygenation is the process of adding pure or almost pure oxygen to your wort, with pure being the better choice. The big brewers do this, so why shouldn’t the small ones. It is easy to do and products are already available to the home brewer (some good, others questionable). The process basically involves injecting oxygen into the wort through a tube. To be effective however, the oxygen must be properly diffused for this process to be truly effective. The oxygen is supplied from a small container of compressed oxygen. It is certainly easier to measure the oxygen added using such a system than "I aerated the wort by shaking till my arms got tired". It is also preferred to use the best grade of oxygen available.

Liquid Bread^®, an innovator in home brewing improvement techniques, was the first to offer a system to homebrewers seeking to improve their brewing process, but more on the Oxynater later. Back to the oxygen.

Will it take longer to make beer if Oxygen is added?

No. In fact, it will speed up the brewing process allowing you to drink your finished beer sooner! The process of adequately adding oxygen to your wort with an Oxynater is more efficient and faster than aeration. And, with increased oxygen resulting in reduced lag times and more vigorous yeast, fermentation will start and end sooner, shaving as much as a few hours to a few days out of the process. Wow, Now I can have my finished beer in 5 days rather than 2 weeks. (Of course, if you artificially carbonate your beer using Liquid Bread’s Carbonater tm, you may be able to take another week to 10 days off the total time by avoiding the wait for bottle conditioning.)

Can too much Oxygen be added to wort?

Excessive oxygen in wort can be harmful to yeast. However, the levels required for dissolved oxygen to become an effective sanitizing agent are very high. Practically speaking, it is unlikely you could add this much oxygen to your wort, even if you radically overused pure oxygen. At Liquid Bread, we have added significant quantities of oxygen to beer, far more than we actually recommend, without any detrimental effects on the finished beer.