ph question

[orlando]

Although I enjoy all the technical aspects of brewing to something of an obsessive level ( ), my more level headed sense tends to agree with fego. The bottom line has always to be do you like your beer, which it appears you do, so let that be the end of it. But, I would feel like you when I found a mystery like this I would want to know what is going on.

The starting place for me would be to find out what the water is or should be in terms of its composition. Cheap way is to find out about YOUR local supply from your provider. Most water suppliers websites these days will at least give you an average value for the major Ions and some indication of alkalinity and pH. As for the latter this is largely irrelevant as although it is typically circa 7-8 across the country the key indicator for us brewers is alkalinity. The reason for that is alkalinity is a buffer that resists the lowering of the pH in the mash by the acidifying effects of the grain. If we understand what that is and take steps to reduce it where necessary then it is this that will allow our grains to get the pH to fall into the right range. I am very suspicious of your pH reading for the tap water, it is very unlikely to be true so suspicion does fall onto the papers, but as Eric points out, they are often accurate enough and in the hands of someone who really understands water chemistry probably good enough. For the rest of us I'm afraid it is a analysis of your water by someone like Murphy's and a digital pH meter like Voltcraft's. I am not a water chemist expert so I have relied on those two things and Brun' water to help me understand how all this works and to help me get some control over this arcane area. The 3 together have improved my beer to a standard I only dreamed of when I started all grain.

So the take home is; if you like the beer that you make, across all styles, you don't have a problem or, about £60 for an analysis, pH meter, Brun water and some cold damp towels to wrap round your head before the pennies begin to drop .

[Eric]

I'll look into it...but referencing my original post, it is the fact that my tap water appears to read ph4-5 that seemed odd (Manchester area).
Adding grain to mash tun would only drop it further, which is what the Johnson ph strips are confirming and this was the crux of my original post.

In my mind most tap water reads at a ph7 (stand to be corrected) or thereabouts and therefore when mixed with grain and poss a little gypsum, it would fall within the 5.3 ballpark that is genreally accepted as the most efficient level for sugar conversions etc.

Does anyone else take a ph reading of their water?
Is it bang on ph7 as expected??

Yes, I think you've got your finger on the problem and I missed it in your original post.

My water is very alkaline, usually 240mg/l CaCO3. It has a pH over 7 and if I were to mash with pale malt and the water untreated the mash would start at about 6.
I think your water has virtually no alkalinity and therefore insufficient buffering properties against the acidity of the malt AND that in the pH strip. When you measured the pH of the water, was it with just a drop or two? If so, could you put a strip in a large volume of water to see if it gives a higher reading? I suspect its pH is higher than what has so far been indicated by the strip.

I've brewed at pH levels less that 5 and the finished beer was good, indeed vastly better than produced above .

If this is the problem, there is an easy solution by using a bottled water with alkalinity of around 200 to 300 for 10 - 15% of your mash water for a near all pale beer. That water will be fine as is for the sparge. If you can, avoid bottled water with a high sodium or magnesium content as they could have the mineral content artificially boosted by sodium bicarbonate or Epsom salts. Avoid using sodium bicarbonate to increase alkalinity.

[Aleman]

I'm based in Blackpool, and my water is similar to most Manchester water supplies (That come of the moors) ie it has very low alkalinity . . . . BUT the pH (both measured by me and the water company - UU) is still around 7.4 to 8.2 . . . and the main reason for this is that water companies artificially raise the pH to avoid corrosion of the pipework.

I do believe that the water in Burnley does drop down to 6.5 on occasion, when it rains heavily and the water runs straight off the peat bogs into the reservoir.

I think the issue is really going to be the pH Strips themselves. Some are fine, and quite useable (I've used These from Hop And Grape and These From The Homebrew Shop), and some are just dire and not really used for anything other than determining if something is Acid, Neutral or Alkaline.

I'm with Orlando and Fego

[Eric]

From the Johnson site........

pH indicators can be regarded as weak acids or bases therefore the degree of dissociation can be influenced by co-solvents such as
salts, proteins, colloids and organic solvents. Temperature is also a key factor which can influence pH and must be considered when
conducting any testing. When carrying out tests using pH indicators, a variety of errors can occur:

the indicator acid-base error
The indicator error can occur as a
result of the acid or base nature of
the indicator dye and occurs only in
solutions that are not or inadequately
buffered. If the buffering capacity of
the solution is low e.g. tap water, river
water, distilled water, strongly diluted
salt solutions, the pH value can deviate
up to one whole pH unit in extreme
cases. That being said, the quantity
of indicator in a test strip is usually in
the range of micrograms therefore the
effect is almost non-existent unlike
liquid indicators where the effect may
be more pronounced resulting in an
erroneous reading.

Phill, go and experiment to develop an appendage if you want, but don't give up on this while you have the means to hand to solve this conundrum. Sixty quid might be spent to greater advantage.

[Aleman]

Eric, based on my own readings comparing several pH papers and my pH meter, I know that they produce wildly varying results using the same water sample. . . the two makes that I recommended produced the closest result to my pH Meter.

One thing that might be worthwhile is for the OP to go to the United Utilites Website enter his postcode and select the detailed report. Look at what they report the pH is, if it is the same as his readings then great, if not then his pH Papers are useless for his conditions.

[Eric]

pH strips are useless for measurements in weak solutions. I accept there must be strips and papers in existence that are not good enough for any purpose, but I've not owned such a product. However, I'm betting Phill's mash pH is what the strips indicate and that those particular strips, specifically designated for beer mashing, will also be helpful in later stages of his brewing.

I'm concerned many brewers have misconceptions about water treatment or are put off advancement of their understanding of the subject unless they can justify the cost of a pH meter and its upkeep.

Recently I had a bit of shock with the influence of sulphuric acid from Murphy and Son compared to their data that caused me to do a significant amount of testing. (Murphy's are aware of the findings). To save time and avoid running out of reagent and indicator on hand I used pH strips to chart progress to the point where I overlooked their limitations. I had a 4ml sample containing indicator for testing with a Salifert kit. It showed a dark blue/green colour and was thought to be about 30ppm CaCO3 and it went through my mind it would be interesting to know its pH. Within an instant of dropping in a pH strip, the liquid was strong pink. Of course, there was no point in reading the pH strip, was there?

[mabrungard]

Eric hit it on the head...the ionic strength of our typical wort is very low. pH strips are apparently reliant upon moderate to high ionic strength to report correctly. In a conversation I had with the manufacturer's (EMD) representative, he provided a paper they had authored that pointed out this potential error source. So at least one manufacturer knows and comments on the issue. I've also seen special pH strips that are reportedly for 'low-ionic strength' solutions.