Biological acidification

[MSK_Chess]

I am really interested in this and have read the article on lowoxygenbrewing more than once. I have one or two questions related to the subject. The author does a two litre mini mash, gets a wort of 1040 and then inoculates it with 8oz (226g) of Pilsner malt. Puts it in a controlled environment of 48C for a few days in order for the lacto to do its thing. Ok so far so good! He then introduces the soured wort into the mash to acidify it to a pH of 5.2. He also introduces it into the boil as a knock out addition. The benefits are enumerated in the accompanying text citing Kunze.

http://www.********************/ingredients/a-sauergut-reactor/

I brew maybe once every two months give or take and have no real need of a saurgut reactor, however I would really love to use biological acidification in my beers.

Ok first of all what is a knock out addition? Please forgive my naivety.
Secondly was the 8oz (226g) of grain milled? does it matter?
Thirdly do you have to keep it at temp of 48C until brew day or can you let the lacto acidify the wort and chill it until brew day? Will this kill the lacto?
Fourthly do you need to keep the temp of the mash initially low (48C) to get benefits from the saurgut. If so for how long would you advise mashing at 48C?
Why doesn’t acid malt suffer in the same way from higher temps.
Do you need to boil your mini mash prior to inoculating it with malt

Honestly this is the most exciting thing in brewing that has happened to me for ages, the idea of introducing a very slight grape/tang element and all the smoothness that accompanies it. If anyone can shed light on these things I would really appreciate it - regards Robbie.

 

[Big Monk]

I am really interested in this and have read the article on lowoxygenbrewing more than once. I have one or two questions related to the subject. The author does a two litre mini mash, gets a wort of 1040 and then inoculates it with 8oz (226g) of Pilsner malt. Puts it in a controlled environment of 48C for a few days in order for the lacto to do its thing. Ok so far so good! He then introduces the soured wort into the mash to acidify it to a pH of 5.2. He also introduces it into the boil as a knock out addition. The benefits are enumerated in the accompanying text citing Kunze.

http://www.********************/ingredients/a-sauergut-reactor/

I brew maybe once every two months give or take and have no real need of a saurgut reactor, however I would really love to use biological acidification in my beers.

Ok first of all what is a knock out addition? Please forgive my naivety.
Secondly was the 8oz (226g) of grain milled? does it matter?
Thirdly do you have to keep it at temp of 48C until brew day or can you let the lacto acidify the wort and chill it until brew day? Will this kill the lacto?
Fourthly do you need to keep the temp of the mash initially low (48C) to get benefits from the saurgut. If so for how long would you advise mashing at 48C?
Why doesn’t acid malt suffer in the same way from higher temps.
Do you need to boil your mini mash prior to inoculating it with malt

Honestly this is the most exciting thing in brewing that has happened to me for ages, the idea of introducing a very slight grape/tang element and all the smoothness that accompanies it. If anyone can shed light on these things I would really appreciate it - regards Robbie.

1.) Knockout = flameout = end of or close to end of boil

2.) You don’t have to mill the grain. The lacto on the grain is on the exterior.

3.) If you want to utilize the oxygen reduction capabilities of the Sauergut, you’ll have to keep it hot until you use it.

4.) You need to mash in low in order to keep the lacto alive to get the oxygen reduction. Doughin in at around 55 °C and holding there while you dough in, get pH right, etc. is suitable.

5.) The difference between Sauermalz and Sauergut is that Sauergut contains live lacto. Sauermalz is sprayed and then dried.

 

[MSK_Chess]

Ok, Cheers Scotty, how long after dough in should I hold it at 48C.

 

[Big Monk]

Ok, Cheers Scotty, how long after dough in should I hold it at 48C.

I would target about 131 °F and hold that while you dough in. The amount of time you spend doughing in depends on your system but slow and steady is the way to go due to doughing in being the biggest source of oxygen intrusion.

It takes most about 10 minutes or so to dough in so after that you can step directly to your first β rest.

 

[MSK_Chess]

Ok I understand, very good. I am pretty excited because I have a 60w encased and waterproof ceramic heater in what would normally be my fermentation fridge at the moment and its easily reached 48C. What about the flame out addition, should we just pull a sample and quickly cool (@20C) to ascertain the pH and adjust accordingly? or can we be a bit more cavalier? What should the pH (@20C) of a pre boiled wort be for a lager/pilsner, anyone know?

 

[MSK_Chess]

ok just some more bits and bobs. I understand the mini mash should be a LODO mash. It may present some difficulties in measuring out such small quantities of SMB so perhaps we would need to make up a larger volume of water and draw from it. Also the head space in our inoculation vessel should be purged with Co2. One question, do we need to have an airlock?

 

[MSK_Chess]

Biological mash acidification has a positive effect on flavour stability. By reducing the pH value of the mash to 5.2, fewer ageing components are formed. The mash acidification should only be used with well modified malts at temperatures above 60 °(otherwise only moderately, because protein dissolution is promoted by lowering the pH value.) - Kunze

this is also of some interest because probably those guys who are using BTB could do away with it in favour of biological acidification.

the redox potential improves, a reduced susceptibility to oxygen thereby develops - Kunze

and for those of us for whom clarity is paramount should consider it,

the chemical-physical stability is better less tendency to protein haze,
the protein excretion improves (better break formation ) - Kunze

so not only will it keep your beer tasting fresh but you will probably get that kind of light grape sensation that you get with German Pilsners.

I am going to attempt a simplified version by using some DME (1 litre, 1040 ) and inoculating it with 125g of Pilsner/lager malt. I have calculated that I only need about 350 ml for my mash (@2% acid) and the rest can maybe go into the kettle at flame out, although practically measuring pH when the wort is at such a high temperature could be problematic.

 

[Paulaner]

To simplify your process you could take 1-2 L of your wort prior to boil and hopping and use that as your saurgut starter depending on how big of a batch you brew. As for shooting for a 5.2 mash PH I'd be careful with that and go for around 5.4 since we're boiling so low the DMS splits in half the time at 5.4 as opposed to 5.2. I've experienced DMS in my beer with a 6.5% boil off and a mash PH of 5.2, and with a 5.4 PH and this % of boil off no DMS. Also, knockout boil PH will be around 5.3'sh and you'll be able to use more of your delicious saurgut to get the PH below 5.1 which will impart more of your grape/tang flavor you're excited about.

 

[MSK_Chess]

I was amazed at how effective Lactobacillus infused wort was in reducing mash and wort pH. I simply made a 1 litre starter with some DME, used 125g of pale malt, was super easy. My mash pH was 5.5 and my post boil pH 5.2. The great thing about it is being able to control the pH at any stage pre boil. The only trouble I had was in measuring the pH for it was difficult to reduce the temperature of the sample fairly quickly. I ended up putting the sample outside in the snow to reduce it quickly. I did not reduce pre fermemted wort to 5.1 but may do so next time depending on the style of beer/lager. It would be good to know roughly how much soured wort to use to reduce an average 5 gallon batch by 1 pH. I think this will require experience.

 

[xdosequisx]

What sort of turnover is required to maintain a reactor? Are those always held at 48C or just until attenuated?

I'm wondering if it's worth setting up a reactor for a 5-10gal every other weekend sort of brew schedule.

 

[Big Monk]

What sort of turnover is required to maintain a reactor? Are those always held at 48C or just until attenuated?

I'm wondering if it's worth setting up a reactor for a 5-10gal every other weekend sort of brew schedule.

Depending on the amount you need per batch (obviously paler beers will require larger doses, etc.) you could probably use 0.5-1 liter per batch. You'd refresh it every batch with new wort to "feed" it and keep it at 48C constantly.

Or, you could just do a Sauergut "starter" for every batch.

 

[xdosequisx]

Interesting, so it won't die off if its held at 48C after the lacto has finished up and reached stationary phase? I'm thinking of starting something along the lines of a 1gal reactor. Does it need to be stirred constantly as well?

 

[Paulaner]

Interesting, so it won't die off if its held at 48C after the lacto has finished up and reached stationary phase? I'm thinking of starting something along the lines of a 1gal reactor. Does it need to be stirred constantly as well?

You'll still need to feed it to keep it alive, which if you brew regularly shouldn't be a problem.

 

[xdosequisx]

So, from reading Kunze and elsewhere, I'm gathering that the culture is grows at 48C until it reaches 2% Lactic acid, after which cell growth becomes stationary. Before reaching stationary phase, the culture must be split or expanded by feeding one part culture with one part diluted (1.040?) first wort. In practice, how long is it expected to take from feed to feed?

Also, why is it important that the mini-mash be LoDO? I would think that any DO in the lacto culture would be consumed prior to the culture being used in a mash, therefore not affecting the final beer.

 

[RPh_Guy]

What sort of turnover is required to maintain a reactor? Are those always held at 48C or just until attenuated?

IMO I'd feed every couple months. It's good to refrigerate between uses after it attenuates. Use an airlock for storage.
Try to avoid temperature shock when it's time to use it and replace the wort. Keep those microbes alive and happy!

Does it need to be stirred constantly as well

Nope, it should not be stirred.

I would think that any DO in the lacto culture would be consumed prior to the culture being used in a mash,

The bacteria do not consume oxygen.
Oxygen will only be consumed if you have yeast fermentation in the "reactor" culture.

You need to mash in low in order to keep the lacto alive to get the oxygen reduction. Doughin in at around 55 °C and holding there while you dough in, get pH right, etc. is suitable.

In fact, I think that's why the "biological acidification" reduces oxygen, it's actually yeast in the culture consuming oxygen.

The photo of the flask here shows active yeast fermentation as evidenced by the bubbles:
http://www.********************/ingredients/a-sauergut-reactor/

... So what's actually going on is that you're adding thermotolerant yeast in mash that consume oxygen.

Question: When Kunze is suggesting mash pH 5.2, is that measured at mash temp or room temp? 5.2 at mash temp is actually 5.4 at room temp, in line with what @Paulaner suggested above.

 

[xdosequisx]

The bacteria do not consume oxygen.
Oxygen will only be consumed if you have yeast fermentation in the "reactor" culture.

Interesting, so then it is a fortuitous coincidence that by inoculating with malt grains rather than pitching a pure culture you are also inoculating with oxygen consuming wild yeasts in addition to being Reinheitsgebot compliant.

... So what's actually going on is that you're adding thermotolerant yeast in mash that consume oxygen.

This brings be back to the mini-mash question though, if there are active thermotolerant yeasts to consume the oxygen, why would the mini-mash need to be lodo?

 

[RPh_Guy]

why would the mini-mash need to be lodo?

In theory, it doesn't.

You'd still get the benefits of oxygen depletion and flavor contribution without using LODO for the culture.

 

[Big Monk]

In theory, it doesn't.

You'd still get the benefits of oxygen depletion and flavor contribution without using LODO for the culture.

The main thing is that you’ll be putting anywhere from 500-1000 ml of the stuff in your Low Oxygen beer. It’s a judgement call whether to make the culture with Low Oxygen wort but I’d opt for it. Then feed it Low Oxygen wort from subsequent batches.

 

[Paulaner]

Just like low o2 beer if you've tasted it you'll notice the difference immediately. My first sauergut culture was a lazy attempt at limiting o2 and then I went all out and it was night and day. If you've drank enough Munich Helles and the outskirts of Munich Helles you'll understand the nuances of sauergut.

 

[RPh_Guy]

night and day.

The finished beer went from night to day just by changing the sauergut to LODO?

 

[Paulaner]

The sauergut culture dramatically changed, which in turned made the beer quite different, but this is using the addition at the end of the boil to control knockout PH.

 

[Vale71]

Interesting, so then it is a fortuitous coincidence that by inoculating with malt grains rather than pitching a pure culture you are also inoculating with oxygen consuming wild yeasts in addition to being Reinheitsgebot compliant.

FYI you can use pure cultures and stil be RHG compliant (or the farce that passes for RHG today). There's nothing anywhere mandating spontaneous fermentation in any step of the process. If this were the case than pure yeast cultures would be verboten as well and RHG compliant beer would taste like crap (which it still sometimes does anyway).

 

[Paulaner]

Sauergut, it's what's for breakfast, at least if you're a brewer.

 

[z-bob]

You'll still need to feed it to keep it alive, which if you brew regularly shouldn't be a problem.

How often does it need to be fed? I assume it's kinda like a sourdough starter in that regard. I brew about once a month, and just intuitively that's not often enough to keep the culture healthy.

Can I use plain glucose for the between-brew feedings?

 

[Paulaner]

How often does it need to be fed? I assume it's kinda like a sourdough starter in that regard. I brew about once a month, and just intuitively that's not often enough to keep the culture healthy.

Can I use plain glucose for the between-brew feedings?

If you can't feed it regularly just store it at around 65°F in a keg and push it with N2 or Co2. It'll last quite a while that way.

 

[xdosequisx]

I see, I was under the impression that it was to be maintained permanently at 118F. At what point should the temp be lowered for storage?

 

[Paulaner]

Once you reach the max acidity you can lower the temp, but be advised you will not get any o2 scavenging benefits since the culture is no longer living once you quit feeding it. You also need to be aware of the possibility that the culture can oxidize if you're not storing it and drawing from it in an enclosed system.

 

[z-bob]

Once you reach the max acidity you can lower the temp, but be advised you will not get any o2 scavenging benefits since the culture is no longer living once you quit feeding it. You also need to be aware of the possibility that the culture can oxidize if you're not storing it and drawing from it in an enclosed system.

Mine is in a glass jug filled to the very top and has an airlock on top. I'm not worried about oxidation. I am concerned about the culture dying completely. (don't care if some of it dies off, as long as it perks up again when I feed it and it consumes all the new sugar) It's been about a month since I fed it last.

Should I pour off half of it (and probably freeze it; it's still good for acidification) and add fresh wort to the jug and see what happens?

 

[Schlenkerla]

Mine is in a glass jug filled to the very top and has an airlock on top. I'm not worried about oxidation. I am concerned about the culture dying completely. (don't care if some of it dies off, as long as it perks up again when I feed it and it consumes all the new sugar) It's been about a month since I fed it last.

Should I pour off half of it (and probably freeze it; it's still good for acidification) and add fresh wort to the jug and see what happens?

You could also make canned wort if you have a pressure cooker. Pull off Sauergut sample and replace it with fresh canned wort. This way you can feed it with brewing. Or just by 1lb bags of DME and distilled water for a quick wort. Just bring to a simmer, chill and add.

Yes/No?

 

[Schlenkerla]

I have a yogurt maker and instant pot that could work as a heating vessel.

The yogurt maker holds about 100-110F with a 48 hour timer.

My instant pot can hold temps from 100-200F for 99 hours.

Hmm - Sous Vide seams to be for more than just meat!!!

 

[Lemmie]

I was reading the wort production chapter (3) of the Kunze. In section 3.2.1.8 Titled “Biological Acidification” the advantages of lowering the ph in the mash were listed with the suggestion “it is therefore advantageous to lower the ph to 5.4-5.5 when mashing. The beta-amylase can be damaged at lower values.” However, Later in section 3.2.1.10 titled “Conclusions for the Mashing Process” Listed as a positive influence on the mash was: “adjusting the mash ph to less than 5.4 and ideally 5.2” this struck me as contradictory due to the negative effects on beta-amylase previously stated.
In a effort to further investigate this issue, I searched HBT and found this thread and this comment:

http://www.********************/ingredients/a-sauergut-reactor/


Question: When Kunze is suggesting mash pH 5.2, is that measured at mash temp or room temp? 5.2 at mash temp is actually 5.4 at room temp, in line with what @Paulaner suggested above.

I followed the link to ******************** and noticed the copied pages from the section 3.2.1.8 I just referred to from the Kunze. However, much to my surprise, the text has been changed from that earlier version where the recommendation was to lower the ph to 5.2 without mentioning the impact on beta-amylase. I have the latest English edition (6) published last June and the previous edition (5) was published in 2014. I am curious what data precipitated this change in the Kunze. I am also curious if anyone has seen the results of any other research on this?

 

[Die_Beerery]

Remember these are still just "translations" to English from German, by "normal folk". However, I think you found some bugs in room temp vs mash temp and vice versa.

 

[Gruel]

I know this is a thread from before Corona, but anyways:

1. Wouldn't lactic acid - even if added before mashing - impart an off flavor to the beer?
2. Is there any advantage to adding lactic acid, versus using an acid rest?

The acid rest (e.g. first step in Palmer table 11) makes the mash take longer, but preparing the lactic acid mash addition seems to take equal or larger time & effort.

 

[Die_Beerery]

I know this is a thread from before Corona, but anyways:

1. Wouldn't lactic acid - even if added before mashing - impart an off flavor to the beer?
2. Is there any advantage to adding lactic acid, versus using an acid rest?

The acid rest (e.g. first step in Palmer table 11) makes the mash take longer, but preparing the lactic acid mash addition seems to take equal or larger time & effort.

Lactic acid? As far as sauergut or mineral acid?

I'm inclined to believe you mean sauergut (SG).

1. If so, yes it imparts a flavor. A flavor that is in all German beer, and one you need to reproduce if you want authentic tasting German Beer.

2. Flavor, ease, time.
Flavor as in #1 above
Ease as in its dosed and measurable
Time as in to get an actual acid rest to work you need a lot of time down low. No only is the mash something we don't want to prolong, doughing in so low is going to hurt the beer, modern malts not only don't need it, your beer quality (foam, body, etc) will directly suffer from it. If time is your argument, see #1 again.

 

[Dustin_J]

I was reading the wort production chapter (3) of the Kunze. In section 3.2.1.8 Titled “Biological Acidification” the advantages of lowering the ph in the mash were listed with the suggestion “it is therefore advantageous to lower the ph to 5.4-5.5 when mashing. The beta-amylase can be damaged at lower values.” However, Later in section 3.2.1.10 titled “Conclusions for the Mashing Process” Listed as a positive influence on the mash was: “adjusting the mash ph to less than 5.4 and ideally 5.2” this struck me as contradictory due to the negative effects on beta-amylase previously stated.
In a effort to further investigate this issue, I searched HBT and found this thread and this comment:

I followed the link to ******************** and noticed the copied pages from the section 3.2.1.8 I just referred to from the Kunze. However, much to my surprise, the text has been changed from that earlier version where the recommendation was to lower the ph to 5.2 without mentioning the impact on beta-amylase. I have the latest English edition (6) published last June and the previous edition (5) was published in 2014. I am curious what data precipitated this change in the Kunze. I am also curious if anyone has seen the results of any other research on this?

A little late here, but reading Kunze is definitely an adventure, especially a lot of the figures which were never translated or done so in a basically incoherently way. Regarding the section on pH & Beta Amylase that you mention, I'm pretty sure that the translation got mixed up in the 6th Edition (maybe earlier) and the concern is primarily about Alpha- (not Beta) inactivation at lower pH values. On pg. 221 it clearly states B-amylase pH optimum of 5.4-5.5 and A-amylase pH optimum of 5.6-5.8. Additionally, the older 3rd edition there's a bullet point in the Biological Acidification section "the range of enzymes is considerably improved because all the important enzymes, with the exception of Alpha-amylase, are activated". This is identical to the 6th edition, except the 6th edition substitutes Beta for Alpha, which points to another possible translation quirk. This oft-cited enzyme temp & pH range would suggest this is the case as well:

https://realbeer.com/jjpalmer/Enzchart.gif

 

[Gruel]

Regarding the Palmer chart of enzyme activity vs pH & temperature, online right now is this color version:

It's missing the phytase acid rest region, compared to your (Dustin_J) b&w version, but table 11 right below it has it (see the link above).

Die_Beerery, yes, I meant the biologically added lactic acid ('sauergut').

 

[Beermeister32]

Does the souring need to be done at 118F? My garage is about 80F currently, would that work, extend the time, etc?

 

[RPh_Guy]

My garage is about 80F currently, would that work, extend the time, etc?

No, not when using a wild culture. The high temp is needed to inhibit yeast fermentation.

 

[Beermeister32]

Makes sense. So 118F is optimum, what might be the upper allowable temp?

 

[z-bob]

Makes sense. So 118F is optimum, what might be the upper allowable temp?

You should be asking what's the lower limit. Then shoot for something between that and 118. (I've made Sauergut at 100F using a handful of pale malt to inoculate it, and it worked very well.)