How do 'oxygen absorption' bottle caps work?

Dedicated brewers will know that beer exposure to oxygen should only occur before fermentation and not after

It's the same with food - oxygen will damage food so that's why many foods are packaged in plastic with 'oxygen scavaging' features - look at potato chips, the bags they come in are filled with nitrogen!

So if you are trying to minimize the amount of oxygen in your bottled beer, mead or wine, you may want to consider using oxygen absorbing caps.

The bottling process can add unwanted oxygen into the beer if you are not careful and too rough with your wort. 

To remediate this you can do things like being careful with your pouring into the bottle and using a bottling wand.

If you want to do more than that, the bottle caps can help remove the oxygen that sits above the surface of the beer and between the bottle cap.

If you are looking to cellar or age your beer, these caps could help you achieve your goal.

Do oxygen bottle caps really work?

Now, let's take a skeptical view of this concept first. 

Do you really need to remove oxygen from the beer bottle?

If you have bottle-conditioned 1000 beers and never had a problem, do you even need to use these crowns?

If you are intending to age beers or extend the hoppiness of your beer, they can certainly give your beer the edge.

The loss of hops aroma can be one of the first signs of oxidation.

In addition, the compounds extracted from hops will can with oxygen, which forms inert compounds that have less aroma and thus a reduction in hop flavor.

Bottle caps which 'scavenge' oxygen from the beer will help prevent or delay this reaction from occurring.

If the food production and beer brewing industries spending millions of dollars doing it, then it surely works.

If you intend to drink your beers quickly, you may not need them.

How do oxygen absorption bottling caps work?

Oxygen-absorbing caps have an internal liner that once activated by water, will absorb oxygen in the headspace of the bottle.

Oxygen absorbing technology is based on oxidation or a combination of one of the following components: iron powder, ascorbic acid, photosensitive polymers, and helpful enzymes (amylase enzyme is really good for brewing actually).

Glucose oxidase is an enzyme that is popular in the elimination of O2 from bottled beer or wine.

The question you need to ask yourself is to what degree do they work and how much of an effect will they have on your beer.

Some brewers think they are only good enough to give worrisome brewers piece of mind!  Given they are only a few cents more per cap, this can make it worth it. 

How do you use oxygen absorbing caps?

These caps activate once you get them wet. 

So once they are capped on, you can invert the beer to wet the inside of the cap and they will stand ready to begin absorbing oxygen. This process starts a day or two after they first get wet. 

>> Side note - if you are adding sugar to your beer bottle at a time, the inversion will make sure no sugar stays in the bottle neck. This is not an issue if you are batch priming the whole wort with sugar)

For clarity, store your brew normally after the inversion.

Many suppliers recommend to not wet or sanitize caps in advance of your bottling session or they will not work correctly. They’ll still close the bottle off from the air like any other cap, but the oxygen-absorbing function will be used up. 

This does mean you can sanitize them just prior to use. 

But that might lead you to ask:

Do I need to sanitize oxygen-absorbing caps?

This author personally no longer sanitizes beer caps. They come out of their bag clean and frankly after 1000s of beers bottled without them, I've never had a problem. 

That said, if it is your standard practice to sanitize caps, then a quick dunk in some Star San is just fine, as long as you do it just prior to bottling and not well in advance. This is because the wetness activates the liner of the cap.

But frankly, we've given up sanitizing beer caps and we've never had any issues - they are kept well clean in bags prior to use.

The choice as the brewer, is always yours!

Check out the range and price on Amazon

Leave a Comment absorption caps, bottle caps, crown, oxygen

Best wort aeration pump systems

The best aeration pumps provide an efficient and inexpensive way to aerate the wort in your primary fermenter.

An aquarium pump forces room air through a properly sanitized tubing. The air is delivered then delivered the wort through a diffusion stone. This promotes rapid absorption into the wort.

So what pumps do this the best?

Smarter brewers than I have worked out that your wort should ideally have an oxygen level of 8 ppm (parts per million) before pitching the yeast.

The reality is that many brewers only achieve between 2.5 - 4.5 ppm if they do not aerate with a pump.

By using this wort aeration system you can probably easily double the oxygenation you might normally be getting.

A brewer who brought this unit on Amazon left this genuine review:

“Works great! Bubbles quite a bit, and foamed out of the top (mainly because I didn't leave enough room), but I didn't have any issues at all. My yeast took off like a bat out of hell when I pitched, which seemed to be better than when I didn't oxygenate in the past. I would highly recommend this to any homebrewer looking to improve fermentation.”

What are you waiting for?

Incomplete fermentation to occur?

Check out the price on Amazon:

Eagle Brewing FE380 Aeration System

The Eagle Aeration System does what you want it to do, quietly and effectively.

Attach the ⅜-inch transfer tubing to the unit and your stone and you will be aerating in no time. 

There’s not much more to say about this unit, it’s basically 'plug and play' once you’ve submerged the stone at the base of the fermenter.

Just bear in mind that the tubing (as with all pumps) will be wound up on arrival due to packaging constraints so you may want to stretch it out a bit so it settles on the bottom of the fermenter.

Check out the price on Amazon:

Using diffusion stones to oxygenate beer wort

Here’s a funny thing we learned.

Diffusion stones are not actually made of stone.

How about that eh?

They are actually made of stainless steel which is added to a porous mold.

They do work a treat in making bubbles get that oxygen into your beer. You’ll want your stone to have a micron level of between .5 to 2 microns. This is pretty standard for brewers.

When using a diffusion stone you’ll want to ensure that you’ve sanitized it in an appropriate sanitization solution (don’t forget the tubing as well!).

I’ve read some punters warn that your hand can leave natural oils on the unit which can then clog it up - I say if you’ve washed your hands prior to use, then you should be fine.

It can be hard to attach a diffusion stone to the tubing. Instead of trying to force it in, place the end of the tubing in some near boiling water for a short time. This should soften the tubing enough so you can insert the stone’s connector part.

When placing your stone in the wort, you want it to get to the bottom of the fermenter, not near the top. If your tubing is a bit curly, you may want to try and straighten it out.

If this continues to be a problem, you may wish to consider using an oxygenation wand which will sit quite nicely in the fermenter, ensuring the oxygen bubbles start at the bottom and filter into the whole wort.

Learn more about oxygen wand kits here!

Leave a Comment aeration, oxygen, pump system, wort

When aeration is good but oxygenation is bad

How to properly aerate wort for brewing

While in some ways beer brewing is simply following a recipe but it sure is not like making a cake. There are some many variables at play.

Is the yeast viable?

How much hops do I need to add?

Is my equipment germ-free?

Is the temperature correct?

And on and on.

There's also one more variable that sometimes gets overlooked in the brewing and bottling processes and that's the role that oxygen plays in fermentation.

Oxygen supports yeast growth and effectively then has an influence on the ABV of one's beer so understanding the best way to manage this element will help improve your beer drinking experience.

First up, let's discuss the:

The relationship between yeast and oxygen

The yeast in your beer requires the presence of oxygen so that is can develop new yeast cell walls. The oxygen is used to develop unsaturated fatty acids and sterols, of which the yeast membrane is built.

Good oxygen levels promote strong yeast which in turn means it can handle high alcohol concentrations which means it was last longer and do a better job on your beer.

An efficient yeast means one gets quicker fermentation times and a reduce chance of a stuck fermentation. This also will mean that you will get fewer off flavors in your beer.

The higher the desired ABV, the more oxygen required

We made reference to it above but if you intend to make a high alcohol beer, you need to create an environment where the yeast can handle that - and a strong yeast is key.

At the same time, you are probably intending to pitch your yeast at a higher rate than you would for a 'session beer' so, all things being equal, you'll want to increase the oxygen ready to be used by that yeast.

How to aerate your wort with oxygen 

Before you aerate your wort the first thing to consider is WHEN.

If you aerate when the wort is too hot (this includes being warm) there is a vastly increased change the oxygen will bind to wort particles. 

If this happens, the risk is that over time these compounds will begin to break down, adding the oxygen back into the beer. The harm occurs as the oxygen can tend to oxidize the hop and alcohols.

This can produce 'off flavors' which are often described as being like 'wet or damp cardboard' or sherry like.

How to prevent oxygen from getting into your beer

We discussed above that aeration at hot temperatures is undesirable - so cooling your wort quickly is the best thing you can do.

Using a wort chiller will quickly bring your beer down to the right temperature so you can pitch your yeast but before you pitch, it's the time to oxygenate.

Carboys

If your wort is in a glass carboy, cover the mouth of the carboy with a cap and gently rock the carboy back and forth to encourage oxygenation of the wort. You can do this with a plastic fermenter too. 

Just make sure you have a firm grip!

If you're making a beer with a kit, once you have the kit in (along with hops and brew enhancer) then I fill it up with water from the garden hose. This will easily add plenty of oxygen to the wort. 

Once your beer is in the fermenter and fermentation is to begin, it's pretty simple to keep the oxygen out - you need to ensure the drum or carboy is tightly sealed and that your bubble airlock / air vent has water in it.

Then try not to move it again!

When bottling your beer, a bottling wand and a steady hand will help to prevent aeration. Do not leave your filled bottles uncapped for too long either!



Other tricks for stirring in oxygen:

• Use whisk. Get in there and use some elbow grease
• Use a beer spoon. Not as efficient as a whisk but a strong arm will make some foam
• Add an agitation rod into a drill such as this mixer.
• Use a siphon tube to spray the wort into the fermenter

Whichever agitation method s used, make sure that your implement is clean and sanitized to prevent risk of infection. 

Another great method is to use a pump system for aeration. Check out this instructional video on how to configure the pump.

If using an aquarium fish style pump, you need to make sure the diffusion stone is clean and sanitized and is small enough to fit into the neck of the carboy. The stone also needs to have a small micron level of  between .5 to 2 to ensure lots of gas bubbles are produced.

For best results, aerate your chilled or cool wort for 20-30 minutes.

When racking beer, try not to disturb the beer too much

When you're racking to a secondary fermenter or to your fermenting bucket it's imperative to prevent the liquid from splashing or getting agitated. When using a siphon it's best to keep it smoothly flowing.

Do I have to oxygenate my beer?

No.

You do not need to proactively aerate your beer, fermentation will still occur.

The point of aeration is that you are trying to give the yeast a leg up.

That said, some brewers are known to starve the yeast of oxygen as this assists with the beer profile they desire. This process is called anaerobic fermentation.

Leave a Comment aeration, oxygen

Is plastic or glass better for fermenting beer?

I saw on the 'net there had been some debate on NOT using plastic fermenters because of the risk of beer infection.

I thought this was a subject worth investigating further.

All I ever use is plastic fermenters and having only ever had one incident of infection which occurred to two different fermenters used in the same batch, I could be confident that I've never had an infection caused by using a plastic fermenter (what would the odds have been?!)

So what's the argument from the naysayers?

The reasoning is that given plastic is more easily scratched than glass those scratches can harbor bacteria so, the risk of infection is greater.

This seems a reasonable argument right?

And the simple solution would be to not scratch the plastic as you are cleaning and sanitizing right?

Given my experience and the fact, there are millions of plastic fermenters safely and happily in use around all corners of the globe, then there is nothing much to worry about.

That's provided of course that you follow a proper cleaning process before you add your beer wort for primary fermentation. 

Any decent beer brewer will tell you that the number one key to beer making success is by adopting methodical cleaning and sanitization practices every time you make beer.

We've covered this need before, but our favorite trick is to use sodium percarbonate and not being shy about using boiling water to kill bugs.

Home brewers around the world often swear by the ability of PBW to get their brewing gear brew ready.

So, to be clear I don't see the threat of infection as a reason to not use a plastic fermenter.

Sure, if they get too old or scratched you might totally want to replace one but on a cost basis when compared to glass carboys, they are a lot cheaper, indeed a check on Amazon shows that a carboy is generally roughly twice the price.

Indeed, if you are new to home brewing, the use of a plastic drum is a great way to start where you don't have to worry about damaging the glass!

Oxygen and beer aging

Aging beer is perhaps a reason that you may wish to use something other than a plastic fermenter. The reasoning here is that it's a bit easier for oxygen to enter the beer via plastic than it is beer.

If you weren't aware, other then when first mixing the wort, beer is best brewed with minimal exposure to O2 - and it's the same when bottling your beer as well.

That said the difference in permeability between glass and plastic arguably negligible when you consider most oxygen exchange is occurring through the bung and airlock.

ALSO, if you are trying to mimic the effect of a barrel-aged beer using oak, then some brewers do consider that some oxygen will help!

What you could do is do your primary fermentation in plastic and then if you intend to age a stout or whatever for a long time, you can transfer it to a secondary glass carboy.

Also (2!) bare in mind that by making such a transfer you create an opportunity for oxygen to enter the beer.

Whatever way you go, you totally need to keep your vessel free from a large amount of oxygen entering as it can assist with the growth of mould or other nasties and we really don't want that do we?

As you can see, it's a vicious cycle of contradictory information!

Leave a Comment aging, carboy, fermentation, oxygen, plastic drum, sanitization