Hot Side Wort Aeration/oxidation In Kit And Kilos

[orwell_g]

Hey guys,

Just been reading through the "how to brew" by john palmer. Great book, and would recommend it to anyone starting out brewing.

One thing that is touched on in the Yeast section is aeration is good, oxidation is bad. It mentions that the generally accepted cut off for hot side wort oxidation is around 27 degrees.

This has worried me somewhat as the kit and kilo instructions appear to create a large oxidation risk/potential in the instructions.

"Dissolve contents of can and other fermentable sugars with 2 litres of boiling water"

Obviously this is hotter than 27 degrees, I would then stir it all up until there are no chunks from the malt, and at this point I add 6-7 litres of refrigerated pre-boiled water and top up to 20-23 litres (depending on the batch I'm making). This finishes at about 22-24 degrees, which would seem ideal for aeration at this point. However, have I already performed a hot side oxidation by following these steps? Should I perhaps add the boiling water, add the refrigerated water, then mix everything up?

Just worried that the process in the can is grossly out ... and I don't want to be ruining all my kit and kilos by oxidation ...

Am I being just too paranoid?

 

[manticle]

Jury is out on whether HSA is even a definite problem with full mash full boil so I wouldn't worry.

 

[bum]

This has worried me somewhat as the kit and kilo instructions appear to create a large oxidation risk/potential in the instructions.

"Dissolve contents of can and other fermentable sugars with 2 litres of boiling water"

Obviously this is hotter than 27 degrees, I would then stir it all up until there are no chunks from the malt, and at this point I add 6-7 litres of refrigerated pre-boiled water and top up to 20-23 litres (depending on the batch I'm making). This finishes at about 22-24 degrees, which would seem ideal for aeration at this point. However, have I already performed a hot side oxidation by following these steps?

If I remember correctly the instructions say to swirl the hot liquid and goop in the bottom of the fermenter until largely dissolved then top up with cold water then stir vigorously. Pretty sure (again, going from memory) it doesn't tell you to thrash it up until it is topped up to full volume. If your initial stirring is an issue (which, as manticle points out, it may not be (I do tend to err on the side of caution and work on the idea that it is best to avoid HSA regardless)) it is because you've decided to stir too hard too early.

 

[the_yobbo]

Is this a pole?

I vote yes to Paranoid

Not because I know what I'm talking about, because I don't, but based on the assumption that those K&K instructions havn't changed in years. If there was anything wrong/potentially wrong with the instructions, then every thread with a newbie question to K&K would have someone post about the danges of HSA. For example, the recommended brewing temperature range

 

[orwell_g]

If I remember correctly the instructions say to swirl the hot liquid and goop in the bottom of the fermenter until largely dissolved then top up with cold water then stir vigorously. Pretty sure (again, going from memory) it doesn't tell you to thrash it up until it is topped up to full volume. If your initial stirring is an issue (which, as manticle points out, it may not be (I do tend to err on the side of caution and work on the idea that it is best to avoid HSA regardless)) it is because you've decided to stir too hard too early.

This particular set of instructions were from a coopers pale ale can. That above is word for word from the instruction set that comes with the can.

The next is:

Top up fermenter with cold water to the 20 litre mark, mix thoroughly with plastic spoon and check temperature for ideally 21-27 degrees

I guess that bolded section is the important part. I'll just substitute that for "aerate thoroughly". There's not much direction on avoiding aeration at what point, so it's a bit vague and open to interpretation.

There is also another step of topping up to 23 litres after that aeration/mixing, so I guess, taking the instructions word for word off the can and what is right/recommended is a different story ...

I guess there's only so much text that can fit on a piece of paper as big as a tin lid.

My process from now on will be:

- Poor on 1.8L of boiled water into fermenter
- Put can and sugars in slowly to avoid splashing
- Top up with refrigerated water slowly again to avoid splashing
- Top up to 20L where it will be 20-24 degrees
- Aerate with whisk or similar aeration device

Let me know if that sounds too mental ...

Haven't had too many problems so far, but I'm getting more and more out with 2 kegs now, and want to rule out any issues I may have with the simple kits and kilos. Once I've got a bit of a stockpile, I'll get more onto straight extracts and ditch the cans ...

 

[manticle]

Of the myriad questions and problems that people have with kit brews, I've never heard anyone who sounds like they have HSA issues.

When I made kits I used to whisk the hot ingredients together in a bowl to mix properly before adding to the fermenter. Never had a brew that tasted like cardboard although I'm not sure how long it's supposed to take. Maybe I just drank them too quickly?

Worth worrying about when you start mash brewing because it's easy enough to avoid but keep it simple with the cans and concentrate on fermentation processes.

Splashing during the anearobic phase of the yeast (once ferment really kicks in) is a different story. Then you need to pay more attention to not splashing, regardless of temp.

 

[orwell_g]

Thanks again for clearing things up Manticle!

 

[bum]

My process from now on will be:

- Poor on 1.8L of boiled water into fermenter
- Put can and sugars in slowly to avoid splashing
- Top up with refrigerated water slowly again to avoid splashing
- Top up to 20L where it will be 20-24 degrees
- Aerate with whisk or similar aeration device

Is there going to be a step where you do something to dissolve the ingredients in the hot water? You can just pick up the fermenter and swing it around so everything becomes combined without any splashing at all. Also curious as to why you've dropped the volume of hot water by 200ml.

 

[orwell_g]

Is there going to be a step where you do something to dissolve the ingredients in the hot water? You can just pick up the fermenter and swing it around so everything becomes combined without any splashing at all. Also curious as to why you've dropped the volume of hot water by 200ml.

Sorry, yep, dissolving is the second step.

The reason I've dropped the volume to 1.8 is due to the size limitations of my kettle . No other reason. Didn't think it would make too much of a difference.

 

[bum]

You're right, that's kinda why I was asking. It'll be fine to use that amount.

 

[beerbrewer76543]

Aeration is easy, just seal up the fermentor and rock it too and fro on an edge of the base. This gets the wort sloshing and splashing around and has been proven to be more effective than using air stones and aquarium pumps :icon_cheers:

 

[bum]

Link to said proof, please.

 

[Nick JD]

Just for some clarification - "oxidation", although it sounds like oxygen, is not only about oxygen.

Adding 4 hydrogens to carbon makes methane - this is oxidation and no oxygen is involved.

There's plenty of good oxidation happeing in the fermenter.

 

[beerbrewer76543]

Link to said proof, please.

http://media.libsyn.com/media/basicbrewing...tionMethods.pdf

http://media.libsyn.com/media/basicbrewing...-08aeration.mp3

Courtesy of:
http://www.basicbrewing.com/index.php?page...wing-radio-2008

:beer:

 

[bum]

All that (the pdf) talks about is time taken to saturate water with O2. It doesn't mention anywhere that the lowest saturation result (75%) is inadequate for brewing purposes. Also worth mentioning that the shaking method requires 15 minutes of fairly vigorous movement of the fermenter to get the reported results.

I do see a reason to not be recommending people be splashing wort about the seal/thread area however.

Horses for courses and all that, obviously. And thanks for the link. Interesting(ish) reading either way.

 

[RobboMC]

Did no-one mention that tap water is full of aeration already?

If you're adding tap water directly to the fermenter then there is your aeration.

Special efforts to aerate a wort should only be needed when a full boil is carried out
as the boiling action drives off the dissolved gases.

In case you're still wondering, stir the boiling water as GENTLY as possible until all ingredients are dissolved,
then top up to finished volume and stir the life out of it.

I have a lovely sample of oxidised beer, but it took more than a bit of a splash to oxidise it.