Mash Ph

[Natebriscoe]

I have been reading through Kunze and see the recommendation to mash at 5.2, but have yet to find the reasoning. Seems the ideal beta and alpha ph are a bit higher than 5.2.

[caedus]

He says a few times that the lower pH helps inhibit LOX reactions. Take a small hit on efficiency (probably less than 1-2% total extract is lost), and have a more shelf stable beer with fresher flavors. I will cruise through and see if I can find an actual page and reference.

[caedus]

Kunze 3.2.1.8 Wort Production (page 237 in V5).

An important measure is mash acidification at the beginning of the mashing process and/or acidification of the wort. The advantages are:

• the range of enzymes is considerably improved because all the important enzymes, with the exception of p-amylase, are activated,

• at low pH-values more growth promoting substances go into solution, e.g. the supply of zinc is increased,

• the extract yield is increased,

• the protein excretion improves (better break formation),

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

• lautering proceeds faster,

• colouring during wort boiling is suppressed,

• the activity of the phosphatases is promoted and they strengthen the buffering capacity through the release of phosphates,

• fermentation is faster due to better trub excretion, a faster drop in the pH and higher degree of attenuation in the cellar,

• filtration is improved by lower viscosity values,

• the flavour is mellower, fuller and softer,

• the hop bittering is more pleasant and does not linger,

• the beer is fresh, and has a fresher, stronger and more characteristic taste,

• the foam has finer bubbles and is more stable,

• the colour of the beer is lighter,

• a better flavour stability is to be expected, particularly as the lipoxygenase is sensitive to pH values below 5.2 and is then no longer effective

• the chemical-physical stability is better, less tendency to protein haze,

• digestion is aided, which is a positive effect of the lactic acid,

• reduction of the biological susceptibility of the beer because of:

• the low pH : beer spoiling organisms no longer grow below a pH of 4.4,

• the higher degree of attenuation leading to a lower amount of non-fermentable sugar, and hence

• a greater pressure towards selectivity of the yeast which forces back the beer-spoiling competitors.

Section 5.2.1.6:

short mashing in time and low mash pH value of 5.1-5.2 reduce the LOX activity.

Hope that helps

[Natebriscoe]

[Natebriscoe]

So what would everyone's thoughts be on a beer that should have a roast character? I find that I like the ph 5.4-5.6 from a flavor stand point. Maybe some antioxidant buffering from the roast malt to allow a higher ph?

[caedus]

You could always mash at 5.2, then raise which chalk later.

Or use only your base/crystal malt, mash at 5.2. Then mash/steep your roasted malts separately and add them to kettle as your kettle acidification addition, targeting 4.9.

[Weizenberg]

It really depends.

Hefebank Weihenstephan published a paper stating that the biological mash acidification to 5.4 had the best sensory results.

Those familiar with Narziss and Beck will recognise a pH of 5.4-5.5 cited in all the examples. Further acidification then occurs 15 min before boil end and sometimes even after the protein break (5.1-5.2).

What suits one's tastes is naturally a matter of personal preference. I doubt an experiment at 2 different pH settings will burst any homebrewer's bank.

[Weizenberg]

[Natebriscoe]

Was listening to a probrewer podcast today on malting. Where it was stated that if the malt kilning reaches 180f, lox is denatured and no longer an issue. I would bet a lot of malts we use reaches 180f.
Maybe, the 5.2 ph may not be necessary for lox reasons.

[Bryan R]