Low dissolved oxygen brewing techniques

[dent]

Have a read of this if you haven't already.
http://www.germanbrewing.net/docs/Brewing-Bavarian-Helles.pdf

I've made a couple of batches of wort using an extension of their techniques and I can confirm that the wort does indeed taste completely different as they suggest - super clean with the aromatics from the freshly crushed malt.

It will take some time to get my process sorted out all the way, so it will take a few more attempts to get the dissolved oxygen levels down to the point required from grain to glass.

The current rig is shown below for your amusement.

 

[neal32]

How does the finished product compare to your old method? Are you measuring DO throughout your process?

 

[MHB]

Good read and some very well thought out answers to a fairly complex problem

Going to need an hellaciously good starter, the recommended pitching range being 20-30X10^6/ml/oP lets call it 25 million, in 23L at 12oP (1.048).
25EXP6*23,000*12 = 6.9EXP12, a fresh Wyeast pack 1EXP11 = 69 packs worth.

Have fun...
Mark

 

[dent]

I have a DO meter but I'm still ironing out the bugs in my process before I can be confident I have removed all sources of O2 throughout the process. I've only just started with this so there's no beer in the glass yet - I can only support what they say that the wort is completely different - seriously the whole activity of brewing has made the shed smell like it never has before - in a good way

I doubt the final beer will be much different at this point if I go along with what they say - the cold side has to keep up with the process and currently I am not able to guarantee the low DO levels required to keep the fresh malt character in there. But I've got a plan set up so over the next couple batches I'm pretty sure I'll be able to get it nailed.

 

[dent]

MHB - There's no particular need to go without the yeast starter if that's what you're hinting - luckily yeast is a great reducer of DO, so that is one part where we can more or less continue with standard lager brewing practice - at least that's what I understand.

 

[manticle]

Came across this a week or so ago, courtesy of another brewer.
Looks really interesting but I need to print out a hard copy and read more thoroughly.

Interested to hear your experience too. Cheers for sharing.

 

[MHB]

MHB - There's no particular need to go without the yeast starter if that's what you're hinting - luckily yeast is a great reducer of DO, so that is one part where we can more or less continue with standard lager brewing practice - at least that's what I understand.

Commercial literature has been talking about Low DO for some time (like 15 years) it never really got a look in until cheap N2 generators became available, since then it been moving right along with the Japanese taking a big lead. The other related area is stoping or reducing the activity of Auto Oxidisation processes mainly the Lipidase enzymes (Lipoxygenase LOX1 and LOX2). All sorts of interesting stuff going on in brewing.

And no I wasn't suggesting you go without a starter, rather that you will need "a frigging enormous one" to get the sort of yeast populations the authors recommend (I liked the understatement).

"The pitching rate we recommend is approximately 20 to 30 million freshly grown cells per milliliter of wort for a 12 Plato beer [4]. This rate is considerably higher than what many
pitching rate calculators estimate, but necessary for the classic cold fermentation schedule"

When typical pitches are 1.0-1.65 Million/mL/oP yes 20 times is a considerably larger pitch. and No I don't think its going to be a good idea to go to all the extra work then cut a corner on the yeast pitch - If you want to do that definitely not in a Helles, do it is something where it wont show as much.

I really think you will need to be pitching most of 500mL of heavy yeast slurry into a 23L batch, so I would be doing a couple of brews back to back just to build up the yeast population.
In a stirred starter you might get to 80 Million cells/mL. Constant aeration maybe 100 Million c/mL. Constant aeration and incremental feeding maybe 200 Million c/mL.
You work out the pitch size. Don't trust MrMalty
Mark

 

[MHB]

Hum my bad
They have actually included the OG in the pitch rate so they are really only recommending 1.6-2.6 Million cells/mL/oP.
Around double what you would be looking for in a typical commercial pitch, something like 4.5-7 Fresh smack packs worth (loosely).
Still a big starter but not as bad as I thought - teach me not to read carefully.
Mark

 

[dent]

Yeah it seemed there was an order of magnitude out in there, but the principle remained the same.

I agree, it has been in the commercial literature a long time. One thing worth noting is that thanks to the ratio of surface area to volume between "home brew" scale and commercial brewing, it means that we have to take much more care to avoid oxidation factors. I've got a vacuum pump at the ready though, so I can also perform all sorts of activities a commercial brewer would consider ridiculous in order to maintain a low O2 level.

Gotta say, I'm encouraged to finally find another factor to manipulate in order to meet or exceed the quality of good commercial euro lagers.

 

[MHB]

N2 has some big advantages, it will actually strip O2 out of solution and its pretty cheap (except for bottle rental), a reg and an airstone and you can knock a lot of the Oxy issues.

Hum - Vacuum Milling - I wonder...
Mark

 

[dent]

I've had a play, vacuum alone won't purge dissolved oxygen from water. I've yet to try with bubbling CO2 through at the same time. I can't think of any easily available gas to purge things with apart from CO2 - I'd use LPG if it wasn't stinky... and flammable.. yeah.

I'm pretty solid on the mash side - I put the grist in dry, then pull a solid vacuum, then allow the boiled water in, through a counterflow chiller which brings it down to mash temps. After that I fill the rest of the mash tun atmosphere with CO2. Theoretically it is air and O2 free for the whole mash.

 

[rude]

Here I am thinking my English Bitters were coming along nicely with esky gravity keggle

Another great post Dent keep em coming

 

[Killer Brew]

I have a DO meter but I'm still ironing out the bugs in my process before I can be confident I have removed all sources of O2 throughout the process. I've only just started with this so there's no beer in the glass yet - I can only support what they say that the wort is completely different - seriously the whole activity of brewing has made the shed smell like it never has before - in a good way

I doubt the final beer will be much different at this point if I go along with what they say - the cold side has to keep up with the process and currently I am not able to guarantee the low DO levels required to keep the fresh malt character in there. But I've got a plan set up so over the next couple batches I'm pretty sure I'll be able to get it nailed.

Your own DO meter? Impressive! Aren't they around $2500?

 

[dent]

Not so much - I think those with the next order of magnitude more accurate are, yeah, but mine has a 0.1ppm resolution and an accuracy I assume fairly worse than that. About $240 delivered. The germanbrewing guys have another model that might be better. I'm a bit dubious about the efficacy of measuring <0.1ppm when you have to expose the substance to air in the first place though... But I'm not super experienced in that topic.

 

[Killer Brew]

amazing how many craft breweries don't have a meter. Some of those send off samples to be tested but others just trust their processes I guess.

 

[dent]

Not much point if you're not going out of your way to control it I guess. I get the impression it's something the mass volume swill brewers are much more interested in than the "craft" brewers are. At least for the time being.

 

[yankinoz]

The article focuses on Helles, but it sounds Iike LO would be beneficial for any brew, even a hop-driven AIPA in which the malt is in the background. If caramel malts are particularly susceptible to oxidation, then the benefits could be huge in brown ales and the like.

Dent, thanks for the link, and I'll try the methods as best I can. Have you tried them with darker beers and ales?

 

[Bribie G]

Some of the nicest UK ales are made by traditional processes that don't seem to worry too much about hot side oxygen. For example this video tour of Arkell's Brewery in Swindon that mostly runs on 150 year old equipment.

 

[technobabble66]

The article focuses on Helles, but it sounds Iike LO would be beneficial for any brew, even a hop-driven AIPA in which the malt is in the background. If caramel malts are particularly susceptible to oxidation, then the benefits could be huge in brown ales and the like.

Could be even more important for APAs, IPAs and various other hops driven beers - I believe O2 is one of, if not the main, killer for hops aroma.
So LO could be a major step up in quality for almost all beers, except maybe those which are more solely driven by yeast flavours/aroma like lighter saisons & hefes.

Great post/thread, dent.
Thanks for bringing it to our attention. Keep us posted on your progress!

 

[tugger]

If you are removing o2 via vacuum you need to shower the inside of the vacuum tank like a sprayball.
This will only get you to 1000 ppb.
If you bubble co2 venting the head pressure it will bring the o2 down to under 10 ppb.
Tap water is around 7000 ppb.