Inexpensive way to aerate wort

[Mork]

Nip down to your local aquarium supplies shop and buy the cheapest pump you can find (mine was under £10). Remember it's not going to be left switched on for days and days on end like it would be in a fish tank, so this small investment will last for years.
At the same time buy a length of tube to fit the air outlet on the pump. The length is up to you, but it's so inexpensive that you might want to buy 3-4 metres. The pump and the tube shouldn't come to more than about £10.

When you get home find a metal paper clip and unfold it so you have a short length of wire. Holding it with some pliers, eat the other end of the wire over a flame (gas hob or similar), then when it starts to glow a little burn small holes in the last 8-10 inches of one end of the tube, spaced about ½-inch apart. You don't need to go all the way through the tube, just one side will do.

When it's time to aerate the wort, sterilise the tube and a stainless steel knife in some solution. Rinse thoroughly with cold water, then tie the last couple of inches or so of the perforated end of the tube around the middle of the knife, which acts as a weight to keep the tube at the bottom of the bin. Connect the other end of the tube to the air-pump and switch on. I recommend leaving it bubbling away for about 5 hours. It's up to you whether you pitch the starter culture during the aeration or immediately after, but I've noticed it seems to be better to pitch at the same time as the pump is switched on.

Sometimes you might get foam creeping over the top of the bin, so paper kitchen towel or a sterile teacloth can be positioned to soak up any dribbles (being careful not to get the towel inside the bin).

The beauty of this method is that that tube can be used again and again just as long as you sterilise it. That little financial investment will pay dividends for many years to come.

 

[ArmChair]

Hi mate,

Don't supose you have any pictures of the finished product do ya?

 

[wezil]

Hi just a couple of tips, keep the pump above the fv or it might back syphon and wreck the pump and your floor!! (or fit a non return valve)! Secondly keep safe and use an rcd, water and leccy arn't a good mix!! Especially when your mind is on beer!!

 

[Mork]

Hi just a couple of tips, keep the pump above the fv or it might back syphon and wreck the pump and your floor!! (or fit a non return valve)! Secondly keep safe and use an rcd, water and leccy arn't a good mix!! Especially when your mind is on beer!!

Yes, good point, I forgot to mention that.

 

[Mork]

Hi mate,

Don't supose you have any pictures of the finished product do ya?

The next time I brew I'll take a photo, but for now the following (crude) diagram gives you the general idea...

The end of the tube is tied around the stainless steel knife, the weight of which keeps the tube end anchored to the bottom of the fermenting vessel to prevent it from floating to the top.

 

[tazuk]

also where is 2 micron filter people talk about :thumb:

 

[Mork]

also where is 2 micron filter people talk about :thumb:

Thanks for mentioning that. There isn't one, but brewers might be able to adjust the rig to include a filter. I suppose I've been risking it a bit by not using one, but I've had no problems so far and have used this method about half a dozen times... running the gauntlet, you might say... I'll have to think about a modification. Forgive me, I'm still new to this.

 

[PD]

a metal paint stirrer to fit my electric drill does me, cost £3, only takes a 3 min whizz and there's froth all over.

 

[pittsy]

i was reading about this and book claimed that only around 10% of oxygen needed can be mixed in even if tools used ( i think it was around 2% if mixed by hand ) and the only way is to inject oxygen into the wort or use a pump like an air stone (or fish tank pump etc if suitable) I'm now looking at getting an airstone etc

 

[PD]

cheers pittsy, didn't know that. However the yeast seem to find the oxygen mixed in adequate

 

[Mork]

i was reading about this and book claimed that only around 10% of oxygen needed can be mixed in even if tools used ( i think it was around 2% if mixed by hand ) and the only way is to inject oxygen into the wort or use a pump like an air stone (or fish tank pump etc if suitable) I'm now looking at getting an airstone etc

From what I've read, the problem with airstones is that they are one-use only. You can't sterilise them because the wort will permeate into them and afterwards it's virtually impossible to clean them thoroughly, so you'd have to buy a new airstone every time. Also, you can't guarantee even the first time that you'll be able to completely sterilise it before use. That's what I read anyway. So, that's why I decided to use a perforated tube, because you can definitely sterilise it every time and thereby save money in the long term by not having to buy new airstones.

 

[oz11]

I've a hop and grape airstone. Providing I switch on the oxygen before immersing in wort, take it out before switching off the oxygen, make sure not to touch it with my bare hands and clean it afterwards it's perfectly fine to re-use.

 

[Mork]

I've a hop and grape airstone. Providing I switch on the oxygen before immersing in wort, take it out before switching off the oxygen, make sure not to touch it with my bare hands and clean it afterwards it's perfectly fine to re-use.

Thanks, it's worth noting... more than one way to skin a pig, as they say! :lol:

 

[wezil]

Hi an air pump WON'T inject oxygen But it will drive of CO2! Even injecting oxygen won't do much more than that. This is a very common missaprehension!! Also the finer the bubbles the better!! Water can only hold so much O2 before it reaches saturation point, unless you increase the atmospheric pressure in the holding vessell. Also you can get plastic airstones (ebay)!! Or try looking for a sintered brass fuel/ air filter (got one running in my fish tank, works a treat)!! (might take some diy to fit tho)!

 

[oz11]

A 60s blast of pure oxygen through a scintered stone will get around 12ppm oxygen into solution

Source: Wyeast Labs

 

[tazuk]

here is how i do mine :thumb: no pumps no airstones cost nowt lol lol :thumb:

viewtopic.php?f=23&t=32287

 

[c_burgess]

I don't want to sound like a naysayer but is aerating necessary? Do brewerys aerate?

I really do appreciate these 'how to' guides and I always give my wort a vigorous stir for a minute when pitching but before I invest I'd like to know if its worth the extra infection risk.

 

[Darcey]

Most micros will use the drop in method. Fill the fv untill all valves are submerged then drop the wort from the top.

Be warned that yeast fermented with pure co2 will not be worth washing and reusing.

D

 

[Aleman]

Be warned that yeast fermented with pure co2 will not be worth washing and reusing.

I think you mean O2 . . . as all fermentations produce CO2.

And you're wrong! the O2 added at the start of fermentation is used by the yeast to build up levels of sterol and ergosterol which they 'store' for use when conditions improve i.e. they get pitched into fresh wort . . .the Sterols are an important component of cell wall formation and function, and if limited will prevent effective cell division and multiplication.

Most strains of brewing yeast require 8-10ppm of O2 for effect cell multiplication, and this is generally obtained by 5-10 minutes vigorous stirring, Ideally the smaller the bubbles the greater the surface area for gaseous exchange, and the more quickly the wort reaches saturation point. This is the reason why inline injection with Air using a Venturi or stainless airstone is so effective, the wort turns milky with the bubbles when its in use. The only issue is dealing with excessive foaming and this can be done by aerating several times before pitching the yeast..

Using Pure O2 is a tricky one, as it is all too easy to over saturate the wort with oxygen which will kill the yeast, however 30 seconds using a sintered stainless airstone immersed in the wort and stirring will achieve 10-12ppm with little effort. I have started oxygenating my yeast slurry prior to pitching, which is having very good results, but does require extra equipment.

 

[The Goatreich]

In the past I've used a sterilised paint stirrer attached to a battery drill for a minute or so, but recently I've placed a sieve on the top of my FV and slowly drained the wort from the boiler through that. It's generated so much foam that I usually have to drain the wort in two stages.