Mash Ph

[Sunter0100]

I live in an area with very soft water and very low alkalinity.

I have received a Murphys report for various styles of beer. I am planning a Stout. The instructions state to add 3.2g of Sodium Carbonate to the mash to increase the Alkalinity by 120ish for a 25 litre batch.

I understand that 3.2g of Sodium Carbonate in 25 litres would increase Alkalinity by 120, however it is only being added to the mash. Therefore the Alkalinity of the mash water is going to be >300?

Questions:

1. Is the Alkalinity levels of the water only important in the mash, or does the boil Alkalinity also need to be higher for a dark beer?

2. Could I reduce the Sodium Carbonate addition so that it justs raises the mash water by 120 Alkalinity and ignore the rest of the water? Or do I need to spread the 3.2g of Sodium Carbonate across mash and sparge water?

3. Will I be able to taste the Sodium Carbonate at this level as I have heard people say they can taste it in beer?

[Aleman]

You should only treat the mash liquor with the carbonate, you need the alkalinity to be low for the sparge liquor.

I tend to use 2g of carbonate (usually potassium hydrogen carbonate instead of anything with sodium in it) to take my alkalinity up to around 100-120 for stouts, but of course it does depend on what is actually in the water to start with as you can see from my water profile it swings a bit . . . I would have loved to have had a result in the middle of summer as I know the alkalinity can be much higher (~135), but Phoenix analytical were not running then.

Just received my latest results from Phoenix Analytical (Neil aka wallybrew)

Water supply name: Blackpool South
Water supply code: Z070

Code: Select all

              28th Oct   11th Feb 
Calcium    -    35.7      (24.3)
Magnesium  -     8.3      ( 3.1)
Sodium     -    16.2      (12  )
Potassium  -     1.0      ( 0.7)

Sulphate   -    68.2      (42.8)
Chloride   -    15.6      (11.1)
Phosphate  -     6.2      ( 4.7)
Nitrate    -     2.1      ( 1.3)

Alkalinity -    67        (32  )

All in mg/l, These figures are the actual measured values from a sample taken on the date specified, analysed by a reputable chemical laboratory. My intention is to have analyses done at monthly intervals to determine the 'trend', when I combine that with my brew day tests of alkalinity and calcium, using the salifert kits I can then draw some fairly safe assumptions regarding what the other ion levels are in the raw liquor.

One other thing I found out was that the salifert kits are surprisingly accurate even at the lower levels of the range as I also checked before I sent the sample off . . . Calcium Spot on, Alkalinity was a little higher, but that was due to use error, so I am now much happier recommending the Salifert kits to brewers for testing alkalinity.

[Sunter0100]

Thanks Aleman.

On that basis I am going to reduce the Sodium Carbonate (I have ordered some now, so will use it) to around 1.5g in the mash to just raise the mash liquor to the desired Alkalinity.

Murphy's also suggest all of the other additions are mixed in with the mash (Gypsum, Calcium Chloride etc). Is there going to be a detrimental effect concentrating all of these minerals in the mash and then diluting them to the required levels as the untreated sparge water is mixed in? Or, would you suggest splitting them between Mash and Sparge liquor?

[Aleman]

My personal preference is to treat mash and 'sparge' liquor differently, Mash gets alkalinity changed, and calcium boosted with gypsum and or calcium chloride, and these salts are added to the grist. Sparge gets alkalinity reduction, and calcium boosted . . . but the salts go in the boiler before I start running off the sweet wort.

At this stage however it does come down to personal preference and practice rather than 'best practice'

[Dave S]

My personal preference is to treat mash and 'sparge' liquor differently, Mash gets alkalinity changed, and calcium boosted with gypsum and or calcium chloride, and these salts are added to the grist. Sparge gets alkalinity reduction, and calcium boosted . . . but the salts go in the boiler before I start running off the sweet wort.

At this stage however it does come down to personal preference and practice rather than 'best practice'

I do the same for the mash but mix my additional salts in with the sparge water and stir well whilst heating. Don't know if I'd be better running the wort onto them in the boiler or not. What do you see as the advantage with that Tony?

[Aleman]

Basically I know that all the salts I put in the boiler end up in the boiler, and do not get stripped during the sparge. Calcium for example can be stripped through a reaction with phosphate from the phytin reaction and also oxalate . . . As I say at this point it's tiny tiny differences, and comes down to an individuals preference and interpretation of the published research.

[Dave S]

Basically I know that all the salts I put in the boiler end up in the boiler, and do not get stripped during the sparge. Calcium for example can be stripped through a reaction with phosphate from the phytin reaction and also oxalate . . . As I say at this point it's tiny tiny differences, and comes down to an individuals preference and interpretation of the published research.

Might give it a try next time and see if I notice any difference, though it will probably be nigh on impossible due to the other variables in play. We'll see.