Biological acidification

[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.lowoxygenbrewing.com/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 lowoxygenbrewing.com 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 lowoxygenbrewing.com 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.)