Total Alkalinity.....my experience

[markp]

I just thought I'd post this as it may help those who are looking in to or just about to start AG brewing.

I'm in the just about to start category - time to get my head round total alkalinity and CRS.

On the water company website (Yorkshire Water), there is a fancy page where you can look at the latest water report and there is also a figure for average water hardness.
The av. water hardness was given as 103.6mg/l and their calculator converts this to 259mg/l CaCO3 or 18.13 clarke Degrees

Being a little unsure I decided to ring them.....they had to get the lab to ring me back.
The lab has given me what they say is the most recent data for total alkalinity and this is currently averaging 110mg/l (CaCO3).

You can see there is a massive difference in the website and the lab result and I probably don't trust either of them in all honesty.
There is a big risk of adding an incorrect amount of CRS and therefore not getting the correct mash pH......and; from what I read, too much CRS will make short work of your boiler element(s).

I had a Salifert test kit delivered today so it will be interesting to see what result I get from it.

 

[Aleman]

What I would suggest you do is to use the test solution, so that you know what the end point looks like, before you test your water. . . I can get a difference between 18 and 28mg/l depending on which end point I take . . . . FWIW in my case it makes no difference to what I'm doing, but just acts as a reassurance point

 

[markp]

Thanks for your post Aleman.

I had come to the conclusion that the test result kit would be the best way to go.

From my research I was aware that it can be quite easy to overshoot the end point.....so I will be looking for the point where it is 'on the brink of changing colour' so to say.
Delving to the depths of my brain & back to uni days; IIRC, with these types of indicators there will probably be a murky/dark grey tinge appearing right before the end point.

I'll probably take 3 tests and do an average before working working out how much CRS I need.
I also plan on re-testing the water after adding the CRS.

 

[markp]

The Salifert test gave me three very close readings, the average of which was 97 mg/l CaCO3

A lot lower than I thought as my water is hard.....so I'm assuming that the majority of my hardness is temperory??
I'd be grateful if anyone had any input on that.

So, the result was a lot closer to the telephoned lab result and way off the water report on the web.
If relied on these results rather than the Salifert result, I would have added too much CRS.....very much so in the case of the web report??

Thanks in advance :)

 

[Aleman]

The Salifert test gave me three very close readings, the average of which was 97 mg/l CaCO3

It's a reliable test

A lot lower than I thought as my water is hard.....so I'm assuming that the majority of my hardness is temperory??

Difficult to tell without knowing you calcium, magnesium and sulphate levels .. . . . Of course hardness is not related to alkalinity. Hardness is the level of Calcium and magnesium in the liquor alkalinity is the level of carbonate/bicarbonate . . permanent depends on sulphate temporary depends on carbonate.

So, the result was a lot closer to the telephoned lab result and way off the water report on the web. If relied on these results rather than the Salifert result, I would have added too much CRS.....very much so in the case of the web report??

I have very little confidence in a lot of the reported figures . . . the United utilities ones for my area are pretty good . .. updated on a weekly basis . . . but many of the figures are only based on a couple of readings . .. not necessarily a good thing.

With the advent of the Salifert kit its a simple quick test to perform for each brew, even if its just for a confidence factor

 

[markp]

Aleman, I'd be grateful if we could take this a little further.....

Sulphate - mean 102 mg SO4/l
Magnesium - mean 6.3 mg Mg/l

I'm totally at ease with using the CRS to adjust the alkalinity, but I don't know where to go from here now.
My readings seem to have tied me in knots.

Thanks in advance.

 

[Aleman]

Mark, There are several things we need to know

Primarily Alkalinity . . . yours is fine as is for brewing darker beers (require around 75-100ppm). for paler beers you need to reduce it to 25-30ppm. . . . but you are aware of this and can do so treating with CRS as required.

Then ideally you need to know and these can normally be found on the in depth analysis from your water company web site

Calcium (Ca2+)
Magnesium (Mg2+)
Sodium (Na+)

Sulphate (SO4 2-)
Chloride (Cl-)

As far as I am concerned the only really important one of these is calcium, and for good brewing practice you need a minimum level of 60ppm . . . I try and arrange for around 120 to 150ppm and achieve this by adding calcium sulphate (gypsum) or calcium chloride. The choice of which salt to use is down to the way I want to bias the flavours of the beer. If I want to bring out the hop bitterness then I go with gypsum, if malt flavours then I go with calcium chloride. Obviously a balanced beer will use a combination of the two . . . but it is not a precise science and really has a marginal effect that can only really be determined if you have the other major factors under control.