Low dissolved oxygen brewing techniques

[Mardoo]

Huh? That doesn't seem to be the conclusion of the article at all.

Fair enough. On third read I realise that my understanding was coloured by the impact his early statement of, "Inches, not feet," had on my first two reads. I don't get the feeling though that he's trying to imply this is revolutionary, however it's clear he's excited about the possibilities.

Don't get me wrong, I've spent the last couple days pricing all-SS counterflow chillers so I could have a chance in hell of giving this a go. I'm definitely not a decryer, as many of the questions addressed by this technique have crossed my mind at one time or another. I'm very interested in the possibilities for the more delicate beers (pinky raisers? ). I had a Helles not long ago from a top-notch home brewer, one that did well in comp, and it was dull. I thought WTF??? This could explain a lot of it.

Unfortunately, due to my level of knowledge I don't think I have a lot to add to the discussion other than links, so I'll sit quietly and listen now, and hopefully find a few good questions to ask. I'll try not to add obfuscation though.

 

[Mardoo]

Dent, any chance that at some point you could run us through the process and equipment changes (other than the ones obvious from the article) that you've made in order to pursue this?

 

[MHB]

Actually the two styles where I have noticed the most impact are Kölsch and Alt, maybe the warmer ferment impacts, possibly the Ale yeasts in these two don't have the reducing power of Lager yeasts, I have noticed they don't reach as low a pH as most equivalent lagers... Speculation.
There are noticeable benefits in controlling O2 in most pale delicately flavoured beers, but some more than others again I'm far from sure why.

Just an aside, if you read the IBD training article I posted earlier you will see that Sodium Metabisulphite is used to adsorb O2, as is Ascorbic Acid (Vitamin C).
But that a blend of the two works better, I am fairly intolerant of SO2, for me less is better, something there to explore.
This is where we need DrSmurto - please anything of reaction rates...
Mark

 

[dent]

I had a go at getting those IBD articles but buggered if I could get the site to work after creating an account.

There has been some talk of different yeasts having an effect on the DO, as the yeast itself produces sulfite, and different strains produce more or less of it.

As to my system..

The main part is the 50 litre keg turned into a mash tun set up for vacuum. I cut a hole big enough to be convenient, then used the lid from another keg cut slightly larger, with a plastic fermenter lid O ring in between the two as a seal. I pull a vacuum with a refrigeration vacuum pump, these do a very good job. The atmospheric pressure forces the lid down harder, so even with a little vacuum it forms a great seal and it impossible to remove.

Inside the mash tun is a stainless braid and plate arrangement which works OK. I run a normal HERMS system with a stainless coil to regulate the mash temperature.

Next to it I have an "HLT". This I have set up on a gas burner to boil in order to remove DO. Once the water is boiling I add the normal mash salt/acid additions plus some sodium metabisulfite. Between the HLT and mash tun I have set up a stainless counterflow chiller with a thermowell on the output.

So I load the *dry* grist into the mash tun. I pull a vacuum all the way - this includes all tubing for the HERMS and to the HLT right to the valve. Then I open the valve on the HLT which lets in the boiling water, through the chiller, into the mash tun - the cold water flow on the other side of the chiller regulates the temperature to be appropriate for the mash.

Once the appropriate amount of water has entered the mash tun, I use the refrigeration gas manifold to swap between vacuum and CO2 - thus filling the mash tun with CO2 and relieving the vacuum.

From here I run the HERMS as usual to continue with the mash.

Once the mash is complete I redirect the HERMS output to the kettle. Once a reasonable amount of wort has been drained, I allow water from the HLT to fill from the top to fly sparge. I pull a partial vacuum on the mash tun at this point and the HLT water will actually get sucked in uphill while the HERMS pump fills the kettle.

The boil continues as usual. At some point during the boil I attach a pump and stainless counterflow chiller and recirculate the boiling wort for 10 minutes or so to sanitise the chiller. Then I let the boil go on without recirc.

The fermenter is another 50L keg. I put some water in it, boil the whole thing on a gas burner to sanitise with the coupler attached, then drain the water, then pull a vacuum on it with the output hose of the wort chiller attached - this pulls a vacuum all the way back to the valve so there should be no air between the kettle and the fermenter. I removed the poppet valve from the coupler-ball-valve-adaptor so I can just jam a silicon hose on it.

Once the boil is done I open the valve on the chilling pump - the wort gets sucked through the chiller into the fermenter from the kettle without having to run the pump.

The refrigeration manifold is used again to top up the fermenter with CO2 when the kettle is empty.

Theoretically I have no oxygen in the 50 litre keg so I can put the lot in the fridge overnight to get to pitch temperature with no harm coming to it.

 

[Mardoo]

Awesome, thanks for the thorough description and pics. Screw pumping liquid, vacuum transfer is where it's at!

What sort of fittings are you using on the hoses that pull vacuum? Anything special you had to do to get them to seal? As I'm building my new system air ingress from fittings is something that's on my mind.

 

[dent]

Just regular HD silicon hose works OK - sometimes it sucks in a bit but never to the point that it closes altogether unless there's a tight bend in it. I originally planned for this - I was going to make a bunch of spirals of stainless MIG wire inserted into the hoses to stop them collapsing, but it turns out OK without that.

I don't use any silly couplers, just barbs and wingnut hose clamps.

Yeah the vacuum transfer is pretty cool, but having to operate a HERMS in the dark sucks - I much prefer to be able to see the flow rate and fluid level.

 

[Chridech]

I'm starting to think bottle conditioning could be a very good thing for this process (zero head-space, of course!).

Fascinating reading Dent, thanks for bringing low DO brewing techniques to our attention. Has me intrigued and thinking how I can adapt my brewing process without engineering a whole new system. Hopefully (but not necessarily what the German Brewing article suggests) there is a continuum of benefit rather than a threshold of 0.5- 1ppm O2 above which all malt flavour benefit is lost.

Bottle conditioning could be good, but there is a lot of bubbling that goes on at the start of a standard bottle fill. Presumably would need to purge each glass bottle with CO2 prior to filling which would be kinda laborious. Attaching your Keg FV to a counterpressure filling cap and filling PET bottles or Growlers via a closed system would work to keep out that nasty O2.

 

[MastersBrewery]

A blichman auto sparge may give you that warm fuzzy feeling for blind fly sparging. If the tun were able to hold both positive and negative pressure you could run the sparge as a closed system too. Crap now you have me thinking!! kk's keggermenter would be perfect.

 

[Mardoo]

If I give this a go I'm going with their no-sparge suggestion, just for simplicity. Of course I'll have to do that on the comparison beer too. I'm a ways off from getting to it though.

 

[klangers]

If only the vacuum pumps being thrown out at work weren't 3 phase...

Interesting read and does make sense. I hadn't noticed any ill effects from HSA in my brews, but as the article says, perhaps this is because the ill effect is an absence of a malt flavour rather than the presence of a negative flavour.

The sealing of all hoses etc is an important point. I often wonder what the shearing about in a pump volute does for the wort, and what the invariable cavitation does.

This seems to be an all-in method. Significant expense for all but the most geared-up brewers to be "compliant" with this standard.

No copper? That also means no brass - complete replacement of all my fittings (yeah yeah better to be SS I know but $$)
No bubbles or leaks means I need to replace all my hoses with better, more expensive connections
Splashing etc is general good practice - but difficult to totally eliminate (unless purging/flooding with inert gas)

The main thing that concerns me, due to the tendency for it to go down a rabbit hole, is the degree to which one floods with N2. I would really rather work out an alternative method instead of having a third type of compressed gas to worry about.

 

[dent]

Yep, no brass - I went and replaced all of my old valves and fittings for stainless. I couldn't use an old plate chiller as that was copper too. You shouldn't have any bubbles or leaks anyhow in a recirculating system. Splashing is never good practice apart from a half-assed wort oxygenation practise for yeast pitching - for that you can still do it if you want as the yeast will consume the DO.

I see no benefit of using N2 over CO2 for purging purposes - pretty sure CO2 is much cheaper since it's liquefied and thus you get much more in a bottle. (Just thought, maybe one - N2 is less likely to dissolve in water and reduce in volume)

The vaccum pump wasn't the biggest expense - $150 delivered though I did already have the manifold and fittings for that.

From what I taste of the wort from this process, the low oxygen method is totally about gaining a better flavour and fresh malt character, not about avoiding a ill effect. For the purposes of this thread "HSA" is on another planet.

Apart from the stainless you could avoid most of the expense to be able to give their methods a go with existing parts - I doubt you'll get a beer that is wonderful forever but you'll get a taste of the difference in the wort.

An old mash tun esky would actually be pretty good for this process I reckon - no recirculation to cause problems, you could put a seal under the lid, drill a 8mm hole to purge with CO2 and put a couple of bricks on it to keep it sealed for the mash.

The vacuum and CO2 etc is me trying to make it foolproof and consistent to operate with no grey area.

 

[MHB]

I think a full volume BIAB would be the easiest to do with low cost.
If you boiled the water (all of it) then let it cool to strike temperature and exclude O2 (gas shield, Met, Ascorbic...). Then mash in very carefully (perhaps gas the malt in a bucket). Maintain a slow gas shield throughout the mash and be careful pulling the bag out. I suspect your O2 uptake would be very low bordering on zero.

CO2 has the advantage of being available and relatively inexpensive and heavier than air. It is much more soluble, it forms Carbonic Acid so its going to affect your pH (how much I don't know), it doesn't strip O2 out of solution.
N2 has the big advantage of actually ejecting O2 from solution, not being very soluble not affecting pH. Downside being another bottle, regulator... expense.

Lots of fun to be had - Have to put a DO meter on the Xmas wish list.
Mark

 

[klangers]

Low oxygen brewing - where TIG welding meets beer lol.

Good info. I feel after reading all this a big gap in my understanding has been filled.

If I was to brew a doppelbock (with cold brewed coffee in at secondary/aging), would I be better off doing a no-recirc, decoction? This way the mash tun lid can be on all the time and no compromise due to my dodgy hoses. Then it's just a matter of purging initially and during transfers to and from the kettle for decocting.

 

[Futur]

Do you really have to go to this much effort to completely isolate your mash from oxygen?

I thought the whole point in the paper was to be able to use SMB (Sodium metabisulfite) in the home brewing enviroment to take the brunt of the O2 during mashing. The SMB absorbs the oxygen at a suggested dosage of 100ppm.

Unless of course you don't want to use SMB at all and want to attempt the Lodo process using equipment only

 

[MHB]

Do you really have to go to this much effort to completely isolate your mash from oxygen?
Snip

Yep! O2 is everywhere and gets into everything, to get zero O2 is really hard work, I think it would require very careful mechanical and/or chemical exclusion.
Mark

 

[Mardoo]

Anyone have some links on how how LDO is accomplished at the professional brewing level? My Google Fu is flaccid today. Not much is coming up.

 

[klangers]

Anyone have some links on how how LDO is accomplished at the professional brewing level? My Google Fu is flaccid today. Not much is coming up.

No links, but from my experience in the field, something like the following occurs:

• Incoming towns water goes through a deoxygenation step in the water treatment plant on its way to the water holding tank
• I'm not sure how the holding tanks are vented, but usually this is to atmosphere ie when the tank drains the volume is replaced by air
• Liquor becomes hot liquor after cooling the previous wort and is transferred to HLT
• Hot liquor is mixed with the grist in a "mechamasher" which is basically a big screw that mixes it all together inline in a pipe
• The mash flows into the mash tun, which is likely to have been steam-purged
• All tuns are covered which allows for control of the atmosphere inside
• After the whirlpool, the wort will never again see the light of day until it is in the bottle
• I've personally never ever heard of, nor seen, any form of gas purging in a brewhouse, ever. I'd suggest that steam barriers are sufficient

The biggest difference is the dedicated de-ox plant, and the fact that everything is hard-piped up together with enclosed tuns. Also, at homebrewing scales we have the additional challenge of a far greater surface area:volume compared to a commercial brewer, and therefore are subject to higher relative dissolution rates of O2.

 

[dent]

at homebrewing scales we have the additional challenge of a far greater surface area:volume compared to a commercial brewer

Bam! This is number one I reckon.

Doppelbock might be one of those styles, like old ale or RIS, that actually benefits from some oxidation. But that is fairly arguable.

I would say recirculating is asking for trouble, if you can get a clean wort into the kettle without it, then, great.

 

[Adr_0]

Awesome info. I should know that oxidation at any step will further stale the ingredient, but I believed the HSA non-existence (everyone said so...) so didn't really worry about it.

I think the cube idea is a good one. Where is the O2 coming from? A lot of water samples we get at work start at 4+ppm O2, but when they are agitated then sealed up, the off-site lab returns 0.1ppm or so.

Essentially the O2 has to come from somewhere - if the water is boiled thoroughly and carefully cubed, although it has potential to absorb O2 it still has to come from somewhere. Can it then be pushed out with CO2 for strike or sparge water?

Curious about the vitamin C and SMB combination. I use vit C for chlorine removal - a massive oxidiser if you didn't already know - but interesting to know if it's effective to reduce O2. Sulphur compounds readily bond to oxygen (2.NaHSO3 + O2 = 2.NaHSO4... Sodium bisulphite to bisulphate) but I'm not sure if the vitamin C products are as readily reactive. If they are... sweet!

 

[Mardoo]

I'd love to hear if you work that out! In what form do you use vitamin C for chlorine removal?