How to lower mash pH?

[arcticus]

First post!

I wandered into my LHBS and was advised that ascorbic acid could be used to lower my mash pH. I haven't tried it yet.

I have been using lemon juice until now which is expensive and not super effective.

Anyone have experience using ascorbic acid to lower mash pH? Is there a better additive?

Cheers

 

[TheMadKing]

Lactic acid is better, it's also important to know the alkalinity in your water profile before messing with acid additions. I recommend checking out the Brun Water website, or wait for Brun himself or Aj Delange to ask a specific question. You definitely need to find out what's in your water first though!

 

[hanuswalrus]

I use small percentages of acid malt in the grist to lower mash pH. Definitely check out Bru'n Water, too.

 

[Derek1985]

I use small percentages of acid malt in the grist to lower mash pH. Definitely check out Bru'n Water, too.

I cut my water with varying percentages of distilled water and use Gypsum, Calcium Chloride and small amounts of Acid malt to get my pH in line for many different styles.

 

[porterpounder]

88% lactic acid. Inexpensive and easy and only takes small amounts.

 

[ajdelange]

I wandered into my LHBS and was advised that ascorbic acid could be used to lower my mash pH. I haven't tried it yet.

This is a calibration point on your local man. Take anything he says in the future with a grain of salt.

Ascorbic acid is indeed an acid but is also a reducing agent. It is for its latter property that it is used in brewing. I have never heard of it being used for acidification of mash before but maybe you should be taking everything I say with a grain of salt.

I have been using lemon juice until now which is expensive

It is?

...and not super effective.

Citric acid (what makes lemon juice sour) is quite effective at lowering pH and, in fact, used to be part of many home brew recipies. I suppose they stopped recommending this because of the citric flavor it imposes.

Anyone have experience using ascorbic acid to lower mash pH?

Not I, surely.

Is there a better additive?

Several. In order of popularity among home brewers they are probably
0. Sauermaltz. Add 1% of totalgrist by weight for each 0.1 pH drop desired
1. Lactic acid 88%. Delivers approximately 11.8 mEq of protons per cc. Available at LHBS.
2. Phosphoric acid 10%. Delivers approximately 1 mEq of protons per cc at typical mash pH's. Available at LHBS
3. Hydrochloric acid. Available at LHBS in UK.
4. Sulfuric acid. Available at LHBS in UK.

 

[arcticus]

I'd like to re-visit this with some data. I have obtained some Lactic Acid but unsure how much to use.

My water is:
Total alkalinity as CaCO3 = 75mg/L
Calcium 30mg/L
Magnesium 2mg/L
Sodium 4mg/L
Chloride 3mg/L
Sulphate as SO4 3mg/L
pH 7.65

Mashing in 22 Litres

Grain bill:
6 kg Pils
1.2 kg Vienna
0.5 kg Wheat Malt
0.5 kg unmalted Canadian Wheat
0.15 kg Flaked barley
0.5 kg Carapils

Brew day today - any advice would be great.

A

 

[Jimbodaman]

brewersfriend.com water calc advanced, works great for me and IMO it's easy to figure out. I've never checked their calculations with a pH meter but my beer has turned out tremendously better since using the calculator to get to 5.4 pH. Just plug your values in and it will tell you how much to add.

 

[catalanotte]

The calculator mentioned by @jimbodaman is great. Looking at your water I think you will be able to drop your mash pH pretty easily with a few grams of gypsum or CaCl. If you want a hoppy beer use gypsum, for a malty beer, use a few grams of calcium chloride. Read up on sulfate:chloride ratio which will guide what you choose as a source of Ca to lower your mash pH.

 

[catalanotte]

Deleted

 

[h22lude]

Brewers Friend or Bru'n Water are the best ones to use. You can use both and average the difference. Remember these are just estimates and it will always be best to test as you go.

Read up on sulfate:chloride ratio which will guide what you choose as a source of Ca to lower your mash pH.

This ratio isn't really important. What is more important is the amount of the individual components. Just match the amounts based on the style of beer rather than any type of ratio.

 

[ajdelange]

I'd like to re-visit this with some data. I have obtained some Lactic Acid but unsure how much to use.

My water is:
Total alkalinity as CaCO3 = 75mg/L
Calcium 30mg/L
Magnesium 2mg/L
Sodium 4mg/L
Chloride 3mg/L
Sulphate as SO4 3mg/L
pH 7.65

Mashing in 22 Litres

The object of acid addition is to neutralize the alkalinity of your water and grains such that the pH of the mash (a mixture of the two) is at a desirable value. Let's use 5.4 as an example here. The water has alkalinity of 75/50 = 1.5 mEq/L. To get a liter of that water from 7.65 to 5.4 would require the addition of 1.37 mEq of acid. This can be calculated using the formulas at https://www.homebrewtalk.com/showthread.php?t=473408. The amount of acid required is in this case 91.5% of the alkalinity and it will always be quite close to that with the exact requirement depending on the source water pH and the desired mash pH. For a desired mash pH of 5.5 here with this water you would need 89.2% of the alkalinity. Rule of thumb: use 90%.

For 22 L of water you are going to need 22*1.37 = 29.48 mEq of acid to neutralize your water's alkalinity to pH 4.5.

Now as other posters have pointed out the calcium in your water will react with malt phosphate to produce a couple of mEq of protons. The number all the programs use is (Ca mEq/L)/3.5 but that number includes protons released in the kettle and was derived from analysis of German lager brewing. The number of protons released in the mash will be less than this but as it is the only solid number we have we will use it. It is 0.21 mEq/L for you water with its calcium hardness of 1.5 mEq/L. Deducting this from the acid required for alkalinity and adding in the smidgeon of acid needed in excess to actually give pH 5.4 to the water requires a total of 30.18 mEq.

Grain bill:
6 kg Pils

It's the same story with malts. Each has a DI mash pH and buffering capacity. To calculate the required acid subtract the DI mash pH from the desired pH from and multiply by the mEq/kg•pH and then the kg of the malt. Here are the data on 3 pilsner malts:
Weyermann Pneumatic Pils: pHdi = 5.62 Buffering: -40.69
Weyermann Floor Pils: pHdi = 5.85 Buffering: -31.30
Rahr Pils: pHdi 5.80 Buffering: -46.27

Supposing you choose the pneumatic pils. Then

(5.4 - 5.62)*(-40.69)*6 = 53.71 mEq

OTOH with the floor Pils it's

(5.4 - 5.85)*(-31.3)*6 = 84.51

And with the Rahr...

(5.4 - 5.80)*(-46.27)*6 = 111.05 mEq

These data illustrate that you can have a base malt acid requirement that varies by a factor of 2 depending on which of three types (for which I have data) of Pilsner malt you chose. Whatever you have will not very probably match any of these and so the major part of your acid requirement will be different. The point is that if software is asking you what color the malt is or what type it is then it is not asking you enough and cannot calculate the correct acid addition for that malt nor estimate mash pH accurately.


The other malts all have proton deficits of their own. More uncertainties are attached to them unless you have data on the actual malt you are using:

1.2 kg Vienna

(5.4 - 5.65)*(-32)*1.2 = 9.6

0.5 kg Wheat Malt

(5.4 - 6.07)*(-44.9)*0.5 = 15.04

0.5 kg unmalted Canadian Wheat

?? Probably something like the flaked barley
(5.4 - 5.64)*(-31.07)*0.5 = 3.73

0.15 kg Flaked barley

(5.4 - 5.64)*(-31.07)*.15 = 1.12

0.5 kg Carapils

(5.4 - 5.2)*(-23.2)*.5 = -2.32

Note that this last malt has a DI pH less that the target and thus it contributes protons to the mix (though not many).

Adding up all the proton requirements including those of the water you would need between 117.6 (Weyerman pneumatic) and 172.9 (Rahr) mEq of acid. At pH 5.4 the strength of 88% lactic acid is 11.44 N (mEq of protons per mL of the acid) so you would need from 117.6/11.44 = 10.3 to 173/11.44 = 15.1 mL of the acid for the mash.

It has been suggested by others that the necessary pH adjustment be realized by addition of calcium. As mentioned earlier Kohlbach's formula applies to knockout, not mash, but assuming we got all the protons he promises in the mash the calcium level required to supply 173 mEq from 22 L of water is 1.130 grams of calcium per liter. Thus one clearly cannot rely on calcium to take care of this level of alkalinity.