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When aeration is good but oxygenation is bad

carboy areation wort shake

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?

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!

stirring wort with a whisk

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 implement into a drill and use that
  • 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 an aquarium pump 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.

diffusion stone for wort oxygenation

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.

How to use foam inhibitor to avoid 'boil over' or a 'krausen explosion'

pot boil over prevention

Beware the krausen! A watched pot never boils right? 


This rule doesn't apply on brewing day.

Even though you are paying keen attention to your boil, it takes but a second for a boil over to happen, making a mess and causing you to lose wort.

But what if there was a way to stop boil over?


Some pundits recommend that you add marbles or ball bearings to the brew to help boil over.

Or use a spray bottle of cold water whenever the foamy beast raises its head.

But if you want to make sure you don't suffer a boil-over, try using a foam inhibitor!

Foam inhibitor or 'defoamer' is a handy trick to keep your beer from boiling over.

A popular product is 'Fermcap-S'. A fancy way to describe it is that it is a "silicone based food-grade emulsion".

There are two main ways to use it - during the boil and during fermentation.

If you choose to use 'Fermcap-S' to prevent boil overs on the hot side, add 2 drops per gallon for a nice rolling boil.

If you wish to use it in your carboy or fermenter to prevent the krausen from escaping the fermenter, then the dosage is only 2 drops at the start of fermentation. If you didn't know, the krausen describes the foamy head that develops on top of fermenting beer.

If you have added your inhibitor during the boil, there is no need to add any to the fermenter as it will carry over.

When used in the fermenter, 'Fermcap-S' increases the bitterness of your beer (retained IBUs) by about 10 per cent.

This sounds dandy but why should I use an inhibitor?


Boil-overs are more likely to be a problem if you are using a smaller pot. Users of fermcap have reported being able to make a 5.5 gallon batch in a 7 gallon pot.

While mess is annoying, the real reason you want to prevent this is that the foaming can cause any top-fermenting yeast to be expelled from the fermenter before it can do its job in the wort. 

This then requires the rest of the yeast to work harder to achieve the final terminal gravity which will not necessarily occur if yeast lost has been significant.

There is also another sweet effect of using an inhibitor like Fermcap it actually can help retain the IBUS from the hops - that is to say, it can help your beer become even more bitter when the product is added to the primary fermenter.

Beer is supposed to be foamy! This seems an odd product to use?


At first thought, using anti foam may seem to be a counter-intuitive idea. It would seem fair to consider that putting something in wort or fermenting beer to control foam will also kill the head on the finished product.

However, when anti-foams are used properly, quite the opposite is true!

Using vegetable based defoamer


Instead of silcone based products, you can also try vegetable oil versions.

Vegetable oil is a known yeast nutrient and will be consumed by the yeast during fermentation of beer before bottling or kegging.

Commercial breweries use it


Big commercial breweries often use defoamers and anti-foamers as part of their beer processing but given that it's not really within the spirit of purity brewing, it appears not many commercial operations will freely admit to adding silicone based products to their beer!

So what are you waiting for? Here's the cheapest Fermcap I have found on Amazon!

Begun, the beer wars have


Begun, the beer wars have.

Actually, this has been happening for a while now.

Big commercial brewers versus the little guy.

Big commercial brewers buying up the little guy.

Big commercial brewers trying to trademark beer lingo like radler.

And everyone hates them for it.

So when Tui attempted to bully Moa brewery a few years back, Moa stood up for themselves in a deliciously brilliant way.

While they are not the littlest guy, let's call them a mid-strength brand. They are on the NZ share market, and at the time of Tui's dig, there was nothing spectacular about their share price but they were slowly picking up sales around the world.

Either way, the diss Tui made as part of their famous yeah right campaign was worty of a retort.

If you haven't read the above very word image, do it now. You'll see the story play out really well. Moa is making the point that Tui is part of a world conglomerate where there a layers of corporations and SHAREHOLDERS.

So attempting to pick on a small fish for their share performance is somewhat ironic and amounts to a form of corporate bullying.

It's also amusing as if we are comparing the flavour of Tui to Moa's product, it's this humble drinker's opinion that Moa has the superior product range.

Sure, Tui was a beer I swilled back in my University days (where my Speights drinking mate used to say of Tui beer, "Tui is a bird and let's leave it at that". And that's about what it's still great for, binge drinking at a Uni Bar or a party or summer BBQ somewhere.

Hey don't get me wrong, Lion Nathan who is owned by mega-sized Japanese company Kirin still make Steinalager, which despite its massive commercialization, it's one of the best beers around. Other drinkers will disagree but for this drinker, there's something really special about that first taste of a cold bottle at the end of the day.

The horror, the horror of Garage Project's decision to withdraw Death From Above

death from above garage project


"Death from Above" has been one of Garage Project's most well known beers for a couple of years now. We've extremely enjoyed the odd bottle when we've had the cash to spare for it was a pricey wee brew, often cited at 12 dollars a bottle in the Supermarkets of Wellington.

It was officially described by Garage Project in it's tasting notes:

"Big, juicy, death. The ultimate combination of fruity, herbal, spicy, and citrus. DFA is largely herbal on the nose with the Vietnamese Mint rearing to go, being pushed up and out of the glass by the also bold mango aroma."

And it was paired with a label which had flash backs to Vietnam War era imagery of a Helicopter reigning Death From Above with Napalm.

It quickly became a very popular beer around Wellington and beyond.

Well it used be popular until Garage Project brewer and co-founder Pete Gillespie completely lost his nerve and withdrew his companies most popular beer from sale as a result of a single contact by an Australian woman.

Brewer Pete Gillespie is reported by Stuff as saying that "ending the beer was his personal reaction to the letter from a Australian woman of Vietnamese descent."

He's also on the record as saying "She wrote a very long and detailed letter to us explaining how upset she was and how the imagery and name had triggered things in her."

I wonder if this woman has also written to every Hollywood film producer who ever released a movie about Vietnam. I wonder if she has written to every author of everybook about the Vietnam War? Has she asked for any books or films in her local library to be removed so that young children are not triggered too? Has she written to Netflix to ask the to stop streaming it's war films?

It's my view that while one can defend movies and books as really exploring the issues surrounding Vietnam as being more 'proper' in taste and treatment of the issue, the moment you publish for profit, everything is in the camp, whether it a beer or the Platoon movie.

I appreciate the letter writer may well have some residual issues with her possible experience with the Vietnam War (it's not made clear and the use of 'Vietnamese decent' suggest may may have born in Australia) but come on.

Unlike Death From Above, Gillespie appears to lack some balls.

What's quite amusing is that when the beer was first released to the market 4 years ago, it was met with some quite verbal resistance from the Returned Servicemen Association.

At the time of release the RSA president Don McIver, who served in the Vietnam War, said he found the advertisement "cheap" and "disrespectful", although he noted New Zealand never used napalm. "It seems to me this is almost celebrating it. It's terrible stuff - I don't agree with it."

Garage Project's other co-founder Jos Ruffell responded at the time that the promotion was "a playful pop culture reference" to to the classic war film "Apocalypse Now". That movie famously opens with an attack which uses napalm.

So let's get this straight.

On release of the beer, the RSA, a respected New Zealand society group that represents soldiers who fought in the Vietnam war makes their displeasure known and Garage Project responds by say it's just referencing a movie.

But now when an AUSTRALIAN of Vietnamese decent says she was 'TRIGGERED', they take their beer off the market?

It just makes Garage Project look like hypocrites and their decision is almost a double insult to the RSA!

We imagine Death from Above clones are about to become pretty popular recipes!

I note that Garage project have deleted all references to the beer from their website however by the power of google cache, I found a deleted blog which actually covered the inspiration of the name:

"The beer was originally going to be called Hopocalypse Now, a hoppy pun pop reference to the cult movie by Francis Ford Coppola. The only problem was that there are 12 other Hopocalypse beers in the world. Perhaps one more wouldn’t have mattered - but not everyone agreed with us. So we made the decision to change the name to Death from Above, the motto of the US Airborne Division, a lateral reference to the famous Ride of the Valkyries scene from Apocalypse Now… and the name of a jolly good band into the bargain"

The post also said "It was never meant to be a controversial brew. It is just meant to be a good beer."

So there's that.


Maybe Gillespie and Reffell can reconsidered their decision and come back with the originally intended name?

Either way, based on comments around the social media traps, I suspect that Garage Project has lost a small amount of goodwill.

There is another possible, less 'genuine' reason - simple marketing and brand promotion.

 It could be that Garage Project have decided withdraw the beer from the mark - maybe it was too expensive to make, not actually selling well. To make this call by way of 'The Letter' gives the brand some publicity - and a chance to increase short term sales before they sell out of the drop - and thus giving extra interest in what ever new beer the team has up their sleeve.

Time will tell.

Update:

The beer has been reborn and repackaged as 'DFA' which means Demus Favorem Amori, Latin for “we choose to stand for love”. Quite the turn around eh?

DFA DEATH FROM ABOVE


Article has been edited slightly in response to some thoughts raised on social media.

Using Malic Acid with wine to reduce the pH level

using malic acid to reduce pH in wine

Did you ever see that episode of Knight Rider when K.I.T.T. was placed in an acid bath and he left simply a shell of a car?

Yeah?

Well, don't use that acid when making wine, perhaps use malic acid instead.

Malic acid is an acid that is found in fruit and quite commonly in grapes and apples. Have you ever had a Granny Smith apple and found it to be quite sour?

That's the malic acid at work. It's quite similar to citric acid in that sense.

As such it's used in all kinds of foods to give that tart flavor. Ever tasted 'Salt and Vinegar' chips?

That's not just vinegar you're tasting...

So why would one use malic acid when brewing wine? 


It's a very handy compound for reducing the pH level of wine.

All good brewers know that both beer, cider, and wine need to be within certain pH level otherwise, the tasting experience will be horrible. The acidity works to counter the sweetness and bitter components of the wine such as tannins.

A wine that features too much acidity will taste extremely sour and sharp and produce a physical response from the mouth and tongue. A wine with not enough acid present will taste somewhat flabby and flat and its intended flavor will hard to discern.

This is why so many wine makers use pH testers (such as the Apera) to ensure their wine is in the correct range.

A word to the wise. If your wine is going to undergo malolactic fermentation (such as red or sparkling) do not add extra malic acid as this will convert to lactic acid.

Which wines suit the addition of malic acid?

  • Most reds
  • Rieslings
  • Gewurztraminer
  • Muscat 

When do I add acid to the wine?


Malic or tartaric acids may be added either before or after primary fermentation.

They can also be added during any blending or aging periods, but the increased acidity will become more noticeable to the drinker.

How much malic to add to the must?


It's a general rule of thumb that 3.4 grams per gallon will adjust the acidity by +.1%. 

It will lower pH less than tartaric acid will which is why some wine makers prefer to use that acid.

Order your acid from Amazon.

What is malolactic fermentation?


Malolactic fermentation or conversion is the chemical process in winemaking where the malic acid that is naturally present in grapes, is converted to lactic acid

Fermentation is caused by a family of bacteria known as lactic acid bacteria.

Malolactic fermentation usually occurs as a secondary fermentation shortly after the end of the primary fermentation. The process is usually undertaken for the vast majority of red wines produced. Some white varieties such as Chardonnay use it as a byproduct of the reaction is a diacetyl which imparts the 'buttery' flavor associated with Chardonnay.

This process helps give the wine a good 'mouth feel' which is something all good beer brewers appreciate.

If you're wondering how beer makers can reduce bitterness and pH levels, they can use gypsum salt and calcium chloride.

How to tell if your brew is infected by bacteria

There's a really simple way to tell if your beer is contaminated


Ready for this life changer?

Drink it. 

If it tastes like the scummiest thing you've ever put in your mouth, it's infected.

If it makes you vomit, it's infected.

If it smells like someone set off a sulfur bomb, it's infected.

If you open the cap and the beer explodes like it has been shaken up a thousand times, it's probably infected. This happens as rogue yeast or bacteria has over carbonated your beer, resulting in too much pressure building. Such an explosion should not be confused with a beer bomb caused by the addition of too much sugar when you primed the beer.

Basically, a good rule of thumb is that if you really have to ask if your beer is infected, then the chances are it probably is.

You can, of course, do a visual inspection of your beer before you bottle it as well. What you are looking for at the top of the wort is the formation of 'pellicle' - which is a collection of microbes hanging out on top of your beer. This may not happen with every infection, however.

The pellicle formation can look a bit like this:

pellicle infection of beer

or even this:

beer infection


Which is a real shame because it's not just the fact that your beer is ruined by bacteria or wild yeast commonly referred to as brettanomyces, it's that you've lost your time - it doesn't matter if you've used a kit or done a diligent boil, you have lost those precious minutes.

You've also lost a bit of cash, which can hurt a little, especially if you've gone and sourced that special wheat yeast from the brew shop or those homegrown hops that you drove 45 minutes to get from a brewing mate who swears they are the best he's ever grown.

So what did you get out of this?

Experience.

It's quite likely that user error caused the infection to occur so maybe there's a lesson here for you that you can learn:

ALWAYS

CLEAN

AND
SANITIZE

YOUR 

BREWING 

EQUIPMENT

I learned from my screw up and have never had an infected batch of beer again and that was like three years ago.

Sure, it can be a pain to do the job right but if you want to have a beer that's right to drink, you gotta clean.

So let's talk about the causes of infection.

The most likely cause is as you've probably understood if you've got this far is that uncleanliness leads to infection. By giving bacteria something to feed on or hide in, you open yourself up to a higher chance of infection occurring.

So, clean your fermenter, brewing spoons, pipes, spigots, taps, mash tuns and whatever else you use on brewing day. There's many kinds of cleaning agents you can use (such as the famous Powdered Brewery Wash) but a bit of elbow grease with damn hot to boiling water will do you justice.

Then, sanitization is key. We have promoted sodium percarbonate many times on this site as we think it just does wonders and since we have adopted it, we've never had a problem.

The best part about using sodium percarbonate?

You’ve probably already got some as it’s found in ordinary laundry soak!

So on brewing - clean and sanitizing everything. Don't be lazy or your beer will be hazy!

The next time you'll want to think about bacteria is bottling or kegging day.

Yep, it's almost a case of literally rinsing and repeating.

Your keg and bottles must be free of any gunk and residue yeast. Given them a damn good clean and then use your sanitizer of choice.

In the case of bottles, my favourite trick is to run them through the dishwasher on the heaviest setting. First I rinse them with water to remove all the sediment etc and then they go in. At the Heavy Duty setting, the dishwasher will use the hottest water it can and that kills the bugs. I then store them in a clean drum under a blanket.

Then on bottling day, a quick soak in some sodium percarbonate solution makes things just right.

You can always tell if you haven't done this part properly because if in your whole batch of bottled beers one or two do not taste right but the rest do, you can reasonably assume the issue was with the individual bottle and not the batch as a whole.

That Rotten Eggs smell


We mentioned that rotten eggs can be a sign of an infected beer. That may well be true but it is not true in every case.

If you have used a yeast strain that produces this kind of smell your beer is OK. If you open a bottle conditioned beer too early, you might be able to get those eggy tones. If you let your beer condition for long enough, that smell will go away as the yeast will have continued to work everything out.

If your beer's water is high in sulphate such as that water source infamously discovered at Burton-on-Trent, England then your beer may naturally have this smell as well - the 'Burton Snatch'
If however, your beer has bacteria that has contaminated your beer, THAT smell is a sign your beer is ruined. How can you tell? Do the taste test and that will give you a big indicator.

If you are making wine or cider, there is another risk vector for your brew. That is the natural yeasts that can be found in fruit that can wreak havoc. Many cider makers will use campden tablets to kill off any wild yeast and then substitute their own yeast more suited to the kind of wine or cider that they wish to make.

The best kettle spiders for straining hops

hops kettle spider tripod

You could be forgiven for wondering what a hops spider is.

Is it some kind of jumping jack or a spider that lives on the hop plant?

Nope, it’s an instrument to help add hops to your boil to help prevent sludge build up from the hops pellets or even the leaves. It’s ideal for preventing clogs in brewing gear and helps make brew day just that little bit cleaner.

The way a hops spider works is it is basically a mesh filter that sits over the building kettle and it simply acts as a strainer for the hops - you get want you want from the hops into your beer and the mess stays inside the filter and is simply removed by taking the spider out.

Too easy eh?

Many commercially made hop spiders will use a mesh of 300 micron as it filters the hops quite well.

If you are using leaves, it is actually a really good idea to use a kettle spider because any stray leaves can easily block a valve or inline filter and that could be a real pain to sort out!

What are the things to look for in a good hops spider?


  • Good micron size filter, 300 is standard
  • Made of stainless steel
  • Features a sturdy tripod that will fit across your kettle or
  • a hook that will fit the side of your kettle

I’ve heard hops filters reduce the utilization of hops. Is this true?


It’s a valid concern but perhaps one that is somewhat over thought but there are several things you can do to make sure you get the efficient hops utilization - and in case you didn’t know, we are talking about the IBUs that go into the hops and thus affecting the bitterness of the beer.

  • Make sure your filter sits inside the kettle quite low, say one or two inches from the bottle. This gives the hops enough surface area in which it can play. Check this before your first brew, not when it's time to add the hops!
  • Speaking of surface area, don’t overfill the hops filter. The hops needs its space, especially if you are using leaves. You don’t want them all mashed together, they should be able to float freely a bit. Hangin' and bangin' Jerry!
  • During the boil, give the hops a bit of a stir, or ‘agitate’ them if you will. Maybe use a brewing spoon for this, and remember you are dealing with hot boiling water so be careful as you usually are. 
  • When you remove the kettle filter, ensure that you let it drain completely so that anything that should go into the beer, is with the beer. 
  • You can always compensate by adding a little extra hops to account for any loss utilization. 
  • Some spiders have a tripod and some use a hook on the side of the kettle. Neither kind is better than the other if you follow the above way to use one.

What is the best hops filter to use?


One of the most popular kind of spiders is the 300 Micron Mesh Stainless Steel Hop Filter Strainer
Suitable for a brew bucket fermenter, you simply hang it to the side of brew kettle during the boil, easy to hang and keep stable.

This brew filter will dramatically keep hop trub from getting in your brew bucket. It's also easy to clean with a sprayer or brush. 

Made of stainless steel it is rust-proof and hot-resistant and if looked after, it will give you a long service life.


DIY  - making your own hops spider


home made hops kettle strainer



While there are plenty of really good hops spiders on Amazon, you may wish to make you own in the spirit of good keen homerbrewers every were. Given they are simple devices to make, if you follow the instructions (like in the below video tutorial) then there’s a good chance of making a handy spider.