PH

Braukaiser

In mashing we tend to target the mash pH to optimize the effectiveness of the most important mash enzymes: the amylases which convert starch into sugar. In room temperature tests the pH optima for alpha amylase has been found at 5.3 and for the beta amylase it is between 5.1 and 5.3 [Briggs, 2004] (see pH and brewing water in Starch Conversion). But when their activity is evaluated at mashing temperatures and the pH of a cooled mash sample is measured it shows their pH optima at 5.7 and 5.4-5.6 respectively. This is the result of a pH shift in the mash that takes place when the mash is heated. In addition to that, the pH optimum of the enzyme is likely to shift as well. As a result, at common starch conversion temperatures (65C/150F) the pH of the mash appears 0.35 units lower than that of a room temperature mash sample [Briggs, 2004]. This needs to be taken into account when looking at pH optima for various mash enzymes. Most commonly, however, the pH optima that are reported in the literature were determined by testing cooled mash samples.

A commonly accepted optimal range for mash pH is 5.2 - 5.7 with 5.5 being optimal for starch conversion activity but many authors report wort and beer quality benefits if the pH is lowered into the 5.2 - 5.4 range [Kunze, 2007][Narziss, 2005]. Kunze in particular lists the following benefits for a mash pH as low as 5.2. Since it is a good and fairly comprehensive list I cited it here. Some of these benefits listed will be explained in the following sections [Kunze, 2007]:

The enzymatic activity in the mash is increased as all important enzymes get activated. (except for alpha amylase which starts to suffer at a pH below 5.6)
More zinc, an essential yeast nutrient, goes into solution
The extract yield (efficiency) is improved
The protein coagulation and precipitation is improved (improved break formation)
The redox potential is improved which results in a lower susceptibility to oxygen.
The run-off speed is improved
The color increase during the wort boil is reduced
Better trub precipitation and faster pH drop lead to faster fermentation and greater attenuation of the beer.
Lover viscosity improves filterability
The taste of the beer is more rounded, fuller and softer. The beer is crisper, more fresh and shows more character.
The hop bitterness is more pleasant and doesn't linger
The foam is more stable and denser
The color of the beer is lighter
Mash oxidation is reduced since the main culprit, the lipoxigenase enzyme, doesn't work well at low mash pH conditions
Haze stability is improved
Beer digestion is stimulated. This is a positive effect of the lactic acid
Susceptibility to microbial spoilage is reduced through
Lower beer pH: beer spoilage organism don't grow below a pH of 4.4
Higher attenuation

Even a pH between 5.2-5.4 is already suboptimal for mashes with large amounts of enzymatic weak malts like Munich type malts. Those mashes are better done with a mash pH above 5.4 which will be closer to the pH optimum of the alpha amylase enzyme. In addition to that, when decoction mashing is used the mash pH should not be lower than 5.4 [Kunze, 2007]. While Kunze doesn't give a reason I assume that it is because boiling of the decoctions lowers their pH which may lead to too low of a mash pH for the already enzymatically weakened decoction mash.

While the targeted mash pH is generally not determined by enzymes other than the amylase enzymes it also has an effect on other enzymes which may be considered in certain mashing schedules.

If a ferulic acid rest is held at 35-40C (95-105F) the release of ferulic acid is reduced if the pH is below 5.7 [Narziss, 2005]. Because of that it is advisable to add any acidulated malt, which may be part of the grist for pH correction, after that rest has been completed.

[1]

Electric Brewery

In brewing, 'residual alkalinity' (RA) is actually what we care about (indirectly) as adding grain and salts will already lower the alkalinity and the buffering power we're left with is called the 'residual' alkalinity. Some books and articles will insist that RA is the most important water parameter when it comes to brewing. They will tell you to target a specific RA for the colour of beer you want to produce. The usual recommendation is that a low RA is best for lighter coloured beers, and higher is better for darker beers. The calculations are complicated and often calculators or nomographs (a type of fancy 2D diagram) are provided. Worrying about RA however is backwards, as RA is not something we target. What matters are the salts (for adjusting the flavour) and the mash pH (for proper starch to sugar conversion). If we do not achieve a proper mash pH after we've added our flavour salts, we simply add some acid to lower the mash pH into the proper range (more on this in a later step). The amount of acid required is usually minimal as we know the water cannot have been highly alkaline (hard), as otherwise we would have not have been able to hit our mineral targets in the first place as some of our starting water mineral levels would have been very high. Highly alkaline water is full of minerals and usually needs to be cut with RO or distilled water first in order to hit our mineral targets before we even begin to worry about mash pH.

…..

If desired, after allowing a few minutes for the salts to dissolve and mix in the boil, take a sample and measure the wort pH using the pH meter. It should be around 5.0 to 5.5 (measured at mash temperature).

[2]

Setting the Record Straight on Mash pH - BYO

Bamforth’s range is: 5.3 to 5.8 (mashtemp) / 5.55 to 6.05 (room temp)
Briggs’ range is: 5.2 to 5.4 (mash temp) / 5.45 to 5.65 (room temp)
Kunze’s range is: 5.25 to 5.35 (mash temp) / 5.5 to 5.6 (room temp)
Lewis’ statement: 5.2 to 5.5 (mash temp) / 5.45 to 5.75 (room temp)

The Kunze temperature reference is anecdotal because his textbook does not reference temperature, and Palmer bases his temperature reference on a conversation he had with Dr. Ludwig Narziss (Weihenstephan Center of Life and Food Science’s former head of brewing science for over 40 years).

When I look at these data, I see two things. The first is that there seems to be a “lost in translation” effect in play, where one camp is arguing a moot point against the opposing camp because of the difference in reference temperature. The second thing is that these ranges are all pretty similar.

Palmer discusses mash pH and beer flavor in his presentation, and distinguishes between optimal pH ranges for extract yield/enzymatic activity and optimal pH ranges for beer flavor. As it turns out the two brewing objectives are not always satisfied by the same mash pH. Go figure! That is another discussion for another day.

[3]

PH Raise from hops

Calculate how many pounds per barrel your dry hop load is, t90 pellets usually sit around a .1-.15ph increase per lb/bl. Take a ph reading before hand, say you’re at 4.2 and you’re dry hopping with 2lbs:bbl, you can usually expect to finish around 4.4-4.5. We use lactic acid to adjust PH cold side, and it’s usually around 100ml of lactic to counteract .1ph increase from dry hopping, but I’m sure that would vary depending on suppliers

pH in Mash Tun and Kettle

pH: Also, here's information from a slide of a PowerPoint on Pilsner production (The Brewing of Pilsner Beers by Alan Taylor Braumeister, VLB Widmer Brothers Brewing Co.) that I found useful:

· Target in Mash Tun: 5.4 to 5.6

This is a compromise between the optimal pH ranges for glucanase (5.0) protease (4.5 to 4.7) and amylase (5.1 to 5.8) enzymes.

Reduces: Wort and beer viscosity,

Increases: Wort color increase, Conversion time, Lautering time, Foam stability, Flavor stability.

Brewhouse efficiency, Attenuation, Perceived hop flavor quality. Fermentation and lagering time.

· Target in Kettle: 5.1 to 5.2

Reduces: Alpha acid isomerization, resulting in a "smoother bitterness. Wort color increase during boiling Possibility of microbiological infection

Increases: Polyphenol-protein trub formation, which leads to better hot and cold breaks

Hope it helps!

Just to be clear. You are talking pH at 68F?

Correct