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  1. 02 Aug '16 11:17 / 2 edits
    Great ones! are there any chemists among you who could advise me on a viable way to measure Ph that does not cost a fortune. Basically I have tried everything and nothing satisfies. I have a cheap PH pen which after calibration worked once then failed. I bought a Ph meter designed for use in soil hoping that it would prove trustworthy in an aqueous solution, to no avail! I purchased litmus test paper but these are not very accurate. What would you suggest please, is a chemical method more accurate than these other methods? Basically I need accuracy to a tenth.
  2. 02 Aug '16 11:32
    I suggest asking your local fish shop. (aquarium fish).
  3. 02 Aug '16 11:57 / 1 edit
    Originally posted by twhitehead
    I suggest asking your local fish shop. (aquarium fish).
    aquarium test kits are chemical test kits but again they rely on their accuracy by mixing elements and waiting for colour change and then comparing it to a chart, they usually go up by degrees or .5 degrees and thats not accurate enough. You do get specialised litmus paper, I may look at that. The problem with digital meters is that they only last for about a year or two.
  4. Standard member sonhouse
    Fast and Curious
    02 Aug '16 13:21 / 4 edits
    Originally posted by robbie carrobie
    Great ones! are there any chemists among you who could advise me on a viable way to measure Ph that does not cost a fortune. Basically I have tried everything and nothing satisfies. I have a cheap PH pen which after calibration worked once then failed. I bought a Ph meter designed for use in soil hoping that it would prove trustworthy in an aqueou ...[text shortened]... a chemical method more accurate than these other methods? Basically I need accuracy to a tenth.
    Here is the trick with Ph meters: you need to clean them out with Di water after every use and keep the sensor tip in Di water to keep it at a 7 or so Ph #, neutral, in other words so it can sense the changes from 7, up to 14 or down to 1 whatever.

    I don't think they make much of a point of that for those instruments but that is the skinny.

    We found that out the hard way, the dang sensors cost's a couple hundred bucks and of course they want to continue selling sensor tips.

    There are also vials of Ph #'s you can get for calibration, say a Ph vial marked 3 and that is the cal level for that Ph #, but they have them from 2 or 3 up to 14 or so and as long as you have a sensor tip stored in Di water then stick it in the cal liquid, you can see how well the instrument performs before you make measurements.

    I think you know what Di water is, "De-ionized'' which means the resistance is up around 18 megs/square cm which is as good as water gets.

    Ordinary tap water clocks in at 3 or so Kilohms because of the contaminants.

    Distilled water clocks in about 100,000 ohms or so, better but not up to Di water standards.

    For our work we have to use Di water at a resistance level of at least 5 megohms or so, which means there are still contaminants but not enough to spoil our cleaning processes.

    18 megs is much better.

    We also use Di water as a cooling liquid against a high voltage, since you can run a meter or so of plastic tubing with Di water for cooling and it can hold off hundreds of thousands of volts, our ion implanters uses voltages in that range and we used to be able to cool them with liquid freon but no more, we have to use other high impedence liquids and Di water is one of them, another is mineral oil, which has its own problems, like flammability. You can't burn Di water

    Anyway, get a flask of Di water and a little glass, like a test tube or some such to keep the tip immersed. That way it won't dry out. Drying out kills Ph sensors, but you can't just store them in tap water, too contaminated.

    If you can't get DI water, use distilled, better than nothing.

    And get Ph cal liquids, say a 3 and a 10 or so, that will give you confidence the tip will do it's job.

    Here is one site that has stuff like that, long URL though:

    https://www.amazon.com/s/?ie=UTF8&keywords=ph+pen+calibration+solution&tag=googhydr-20&index=aps&hvadid=112600235440&hvpos=1t1&hvexid=&hvnetw=g&hvrand=378889369978776337&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_60mnx47nbm_b

    Looks like they have just 2 levels, 4 and 7.

    This forum talks about how to make your own cal liquid, Potassium Choride and Di water, probably cheaper just to buy already made:

    http://www.rollitup.org/t/way-to-calibrate-ph-meter-without-solution.282200/
  5. 02 Aug '16 13:45
    Originally posted by sonhouse
    Here is the trick with Ph meters: you need to clean them out with Di water after every use and keep the sensor tip in Di water to keep it at a 7 or so Ph #, neutral, in other words so it can sense the changes from 7, up to 14 or down to 1 whatever.

    I don't think they make much of a point of that for those instruments but that is the skinny.

    We found ...[text shortened]... uy already made:

    http://www.rollitup.org/t/way-to-calibrate-ph-meter-without-solution.282200/
    I have unlimited access to DI water, I use a resin from India, Tulsion MB-115 which filters it and measure it with a TDS meter to 0ppm, its awesome. The pH pen I bought came with two solutions for calibration but its just too cheap to be reliable and I am too much of a Scrooge to pay top dollar for a decent one! especially if it only lasts a year or two. I only need to measure a very narrow band from about 5 - 7 pH but it needs to be accurate to a tenth, 5.3 etc There is a specialised litmus paper that ranges from 4.2 - 6.4 which would do nicely
  6. 02 Aug '16 14:49
    Originally posted by robbie carrobie
    aquarium test kits are chemical test kits but again they rely on their accuracy by mixing elements and waiting for colour change and then comparing it to a chart, they usually go up by degrees or .5 degrees and thats not accurate enough. You do get specialised litmus paper, I may look at that.
    Aquarium kits come in a variety of versions with varying accuracy or preferred ranges. Some are chemical test, others use strips and others are digital meters.
    My point is that if you want cheep then the aquarium people are your best bet as they are probably by far the biggest market for home ph test kits.

    The problem with digital meters is that they only last for about a year or two.
    So buy one every year. They aren't that expensive are they?
  7. Standard member sonhouse
    Fast and Curious
    02 Aug '16 18:46 / 1 edit
    Originally posted by robbie carrobie
    I have unlimited access to DI water, I use a resin from India, Tulsion MB-115 which filters it and measure it with a TDS meter to 0ppm, its awesome. The pH pen I bought came with two solutions for calibration but its just too cheap to be reliable and I am too much of a Scrooge to pay top dollar for a decent one! especially if it only lasts a year or ...[text shortened]... 5.3 etc There is a specialised litmus paper that ranges from 4.2 - 6.4 which would do nicely
    Is this for beer or fish? BTW, just measuring PPM doesn't get you to real DI water. Real DI is measured in parts per billion. The real test is to meaure the resistance with a DI water tester. There is one we use from a company called Myron L

    EP meter, cost's about 400 dollars and is battery powered which gives us good DI water data. It is not that easy to use but it is portable, it is easy to put water in the little cone shaped sensor area but getting reliable readings takes some skill, rinsing it out with the best water you have, unless you are at something like distilled water level which as I said clocks in at about 100,000 ohms/square cm. Di water goes up to 18 MEGohms which is over 100 times the resistance.

    That is the true measure of DI water, not the PPM count. Ours is called the Myron L Conductivity Meter. Handy for spot checks of DI. You just have to rinse out the little cone shaped cup a few times to get rid of atmospheric dust and moisture and such, they bring the readings down if you are testing actual 18 meg water.

    My guess is you don't have full DI-ness, I doubt it would clock in even at one megohm. Just a guess but the systems we use are very complex with reverse osmosis filters plus the resin exchanges plus rough input filters and such and a 200 gallon holding tank made of very high quality plastic, maybe teflon. But the last place I worked had that times 3! Also Ultraviolet irradiation that killed bacteria and fungus.
  8. 02 Aug '16 19:29 / 1 edit
    Originally posted by sonhouse
    Is this for beer or fish?
    He wants it for beer. I brought up the fish because I think that is the cheapest source.

    BTW, just measuring PPM doesn't get you to real DI water. Real DI is measured in parts per billion.
    I don't think he needs DI water for anything. You won't magically make the meter last longer just because you washed it with extra extra pure water. Distilled water should be more than sufficient for his purposes.
    It would be interesting to know what actually wears out on the meters he uses.
  9. Standard member sonhouse
    Fast and Curious
    02 Aug '16 20:23
    Originally posted by twhitehead
    He wants it for beer. I brought up the fish because I think that is the cheapest source.

    [b]BTW, just measuring PPM doesn't get you to real DI water. Real DI is measured in parts per billion.

    I don't think he needs DI water for anything. You won't magically make the meter last longer just because you washed it with extra extra pure water. Distill ...[text shortened]... or his purposes.
    It would be interesting to know what actually wears out on the meters he uses.[/b]
    I think what wears out is the thin glass that is micro perferated and if it dries out, the little holes gets filled and dries up not allowing the liquid to penetrate to the electrode. That is why we kept the sensor tips in liquid, like DI water, 24/7 to be ready for calibration and use.
  10. 02 Aug '16 21:24 / 1 edit
    Originally posted by sonhouse
    Is this for beer or fish? BTW, just measuring PPM doesn't get you to real DI water. Real DI is measured in parts per billion. The real test is to meaure the resistance with a DI water tester. There is one we use from a company called Myron L

    EP meter, cost's about 400 dollars and is battery powered which gives us good DI water data. It is not that easy t ...[text shortened]... t place I worked had that times 3! Also Ultraviolet irradiation that killed bacteria and fungus.
    Its for measuring what is termed 'the mash acidity', that is the acidity of malted grain as its infused in water at temperature to foment certain enzymes. The pH is critical to the process not only for successful conversion of starch into sugars and the break down of proteins, but you can actually tailor the pH to the style of beer that you are making. The optimal pH is considered to be 5.3 but can go as low as 5.1 or as high as 5.6 depending on the style.

    In places with high alkalinity like London and Edinburgh they became famous for producing dark beers because the acidity produced by the roasted malted grains balanced out the alkalinity. The opposite is true of places like Pilsen where they have ultra soft water which is more suited to light beers. The water is so soft that it doesn't have enough minerals for it to reach the proper pH so they have what is called an 'acid rest', roughly they leave the grain at a temperature of 35 Celsius to produce a weak acid.

    Before the turn of the (last) century, when the interaction of malt and water chemistry was not well understood, brewers in Pilsen used the temperature range of 86-126°F to help the enzyme phytase acidify their mash when using only pale malts. The water in the area is so pure and devoid of minerals that the mash would not reach the proper pH range without this Acid Rest. Most other brewing areas of the world did not have this problem.

    Pale lager malt is rich in phytin, an organic phosphate containing calcium and magnesium. Phytase breaks down phytin into insoluble calcium and magnesium phosphates and phytic acid. The process lowers the pH by removing the ion buffers and producing this weak acid. The acid rest is not used nowadays because it can take several hours for this enzyme to lower the mash pH to the desired 5.0 - 5.5 range. Today, through knowledge of water chemistry and appropriate mineral additions, proper mash pH ranges can be achieved from the outset without needing an acid rest.

    http://howtobrew.com/book/section-3/how-the-mash-works/the-acid-rest-and-modification
  11. 02 Aug '16 21:35
    Originally posted by twhitehead
    Aquarium kits come in a variety of versions with varying accuracy or preferred ranges. Some are chemical test, others use strips and others are digital meters.
    My point is that if you want cheep then the aquarium people are your best bet as they are probably by far the biggest market for home ph test kits.

    [b] The problem with digital meters is that t ...[text shortened]... y last for about a year or two.

    So buy one every year. They aren't that expensive are they?[/b]
    Its eighty bucks for a basic good one and about 300 bucks for an awesome one and the cost does not justify its usage for I would be using it about six times out of the year, that adds considerable overheads to a single 23 litre batch of beer.
  12. Subscriber AThousandYoung
    Do ya think?
    02 Aug '16 22:30
    I use this one:

    http://www.ebay.com/itm/new-hanna-hi-98129-ph-ec-tds-conductivity-tester-meter-/300511749866
  13. Standard member sonhouse
    Fast and Curious
    03 Aug '16 03:23 / 5 edits
    Originally posted by AThousandYoung
    I use this one:

    http://www.ebay.com/itm/new-hanna-hi-98129-ph-ec-tds-conductivity-tester-meter-/300511749866
    One micro Siemens, the max for that sensor is only one megohm, it misses DI water specs by 18 to 1, DI goes to 18 and change megohms/sq. My Fluke DVM can do that

    That said, it does a lot for the buck. My Myron L goes to full 18+ megs from a water sample you put in a little cone shaped cup. It also goes down far enough to measure tap water resistance. But it costs a lot more but it was worth the price, it gives very accurate readings once you properly flush out the sensor cup volume with good DI water flush.

    I was surprised how low the resistance gets when run through PVC pipes or Teflon till some flows down the drain, then the resistance goes up an order of magnitude. That is when you actual clean stuff with DI water.

    But that doesn't help Robbie in his quest for Ph measurement.

    If I wanted the thing to last a long time I would consider putting it more or less full time in the mash, keep it wet. But that may not work for brewing purposes.

    But you do need to keep the tip wet with the best water you can get, DI if possible. Less dissolved solids means less chance of clogging up the permeable glass interface.

    I've also seen litmus paper that has several Ph levels on the same paper and you read it out by color. Breweries should have developed Ph sensors in the 5 to 6 range specifically. Maybe you can contact a micro brewery in the area, maybe they know such a specialized device.

    Aha, I gargled this:

    http://blog.hannainst.com/measuring-the-ph-of-mash-in-the-brewing-process/

    They recommend a Ph meter specifically for brewing. Don't know the price.
  14. 03 Aug '16 07:19
    Originally posted by AThousandYoung
    I use this one:

    http://www.ebay.com/itm/new-hanna-hi-98129-ph-ec-tds-conductivity-tester-meter-/300511749866
    what yah growin man!
  15. 03 Aug '16 07:36 / 1 edit
    Originally posted by sonhouse
    One micro Siemens, the max for that sensor is only one megohm, it misses DI water specs by 18 to 1, DI goes to 18 and change megohms/sq. My Fluke DVM can do that

    That said, it does a lot for the buck. My Myron L goes to full 18+ megs from a water sample you put in a little cone shaped cup. It also goes down far enough to measure tap water resistance. ...[text shortened]... he-brewing-process/

    They recommend a Ph meter specifically for brewing. Don't know the price.
    An awesome piece of kit but its 400 bucks which is not excessive. If I were a small microbrewery producing commercial beer/lager I would certainly get this.

    Yes the article makes the point that temperature is paramount and what a home brewer basically has to do is extract some of the liquid and reduce it quickly to 20 Celsius by putting it in the freezer and then measure it. I actually use a spread sheet that takes all of the important parameters into consideration, starting pH of the water, how much calcium, magnesium, chloride, sulphate, bicarbonate and sodium, hardness (temporary and permanent) alkalinity and residual alkalinity to accurately estimate the 'mash', pH. Its really quite interesting. This one was designed by Martin Brungard who is a licensed civil and environmental engineer specialising in water resources.

    https://sites.google.com/site/brunwater/water-knowledge