Oxygen addition when bottling

[northernltz]

Hello Beer Guru's

So I have read several posts about the potential trouble adding air/oxygen to beer in the fermenter can cause. So, if I have this right, the wort needs to be oxygenated when going into the fermenter so the yeasties have O2 to consume to multiply. Then when the oxygen is gone, the yeast get to work on the sugars and make the golden brew we all love. So, when fermentation is done after 1-3 weeks, a typical beer is ready for bottling. The next step would be to add a sugar to the wort/beer to give the yeast another round to consume to carbonate the beer in the bottle. Do I need to re-introduce oxygen to the beer prior to bottling as well as the corn sugar?

Kurt

 

[Jayhem]

You got it on the first part.

When you bottle prime, NO you do not want to add more oxygen. Oxygen allows yeast to MULTIPLY and build more yeast cells which is essential during primary fermentation. After fermentation with a the lack of oxygen in the beer the yeast left in suspension from primary fermentation will be plenty of numbers to eat up the small amount of priming sugar and fart out enough C02 to carbonate.

In other words, yeast don't need oxygen to eat sugar and release C02. They do need oxygen to grow & multiply.

 

[JR_Brewer]

No! Do not re-introduce oxygen after the initial fermentation.

 

[CBMbrewer]

DO NOT add oxygen when bottling! Yeast need o2 during the first phase of fermentation. After that they go through anaerobic fermentation the does not require oxygen. They produce co2, alcohal and other various compounds during this time. co2 is all you need when carbonating. Adding oxygen after fermentation will likely oxidize your beer and substantially diminish its shelf life.

 

[IL1kebeer]

You will inadverantly introduce a small amount of oxygen when bottling no matter how careful you are. The yeast should take this up when they referment in the bottle. So with normal racking conditions you should be fine. You will run into problems if you purposely aerate your beer or if you splash excessively.

To get into more detail, yeast can ferment both with or without oxygen. They do it more effectively with oxygen. The amount of oxygen can affect cell health and growth rates, which has an effect on flavor. In the case of bottling, off flavors due to a lack of oxygen shouldn't be an issue since the amount of yeast and fermentable sugar is so small. Additionally, pretty much all of the flavor compounds have already been created during fermentation so the small amount created during bottle conditioning won't make a noticeable difference. However, off flavors due oxidation will be an issue and that is why we don't purposely oxygenate.

 

[BigFloyd]

do i need to re-introduce oxygen to the beer prior to bottling as well as the corn sugar?

Kurt

no

Dissolved oxygen is use by the yeast to engage in aerobic respiration during the lag/reproductive phase of fermentation when the cells you pitched are replicating. After that, they transition to anaerobic fermentation. Once that occurs, the introduction of additional O2 into the process is not helpful and will lead to the beer becoming prematurely stale.