UserNameGoesHere Senior Member Joined: 11 Dec 2006 Posts: 10 Location: San Diego Expertise: I love coffee
Posted Thu Jun 7, 2012, 10:21pm Subject: For those who measure their water, what TDS and pH meters do you use?
I am looking at the HM brand TDS meters on Amazon, but wondering what the difference between them is. There's the TDS-3, TDS-4, and TDS-EZ. They all seem the same to me. Also, I have no idea about pH meters.
Posted Fri Jun 8, 2012, 7:24am Subject: Re: For those who measure their water, what TDS and pH meters do you use?
UserNameGoesHere Said:
I am looking at the HM brand TDS meters on Amazon, but wondering what the difference between them is. There's the TDS-3, TDS-4, and TDS-EZ. They all seem the same to me. Also, I have no idea about pH meters.
Just got a TDS-EZ to replace a lost one that I had borrowed. So far, it looks like it works. Distilled reads ~000 - 003, my "controlled" water reads ~125 (and generally around 7-8 DH which implies that pretty much all of my cal-mag hardness IS TDS), and my normal well-water is around 255-265ppm.
pH meters - they're about as fragile as wet toilet paper. I've broken two, getting another cheap one to replace it (again, borrowed). One was cheap. One was expensive. Seemed like both were fragile. My strategy is to treat them like a pen, get a cheap one that seems to work. My plan is to cal with the solution, and check a kept sample of vinegar - or eventually get some lo and hi pH solutions.
Also, pH meters need to be stored in neutral liquid, so factor in a bottle of 7.0pH solution (also required for calibration). If you get a more expensive one, make sure you get one that you can replace the sensor, and understand the sensor replacement cost.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Sat Jun 9, 2012, 8:54pm Subject: Re: For those who measure their water, what TDS and pH meters do you use?
Netphilosopher Said:
pH meters - they're about as fragile as wet toilet paper. I've broken two, getting another cheap one to replace it (again, borrowed). One was cheap. One was expensive. Seemed like both were fragile. My strategy is to treat them like a pen, get a cheap one that seems to work. My plan is to cal with the solution, and check a kept sample of vinegar - or eventually get some lo and hi pH solutions.
Also, pH meters need to be stored in neutral liquid, so factor in a bottle of 7.0pH solution (also required for calibration). If you get a more expensive one, make sure you get one that you can replace the sensor, and understand the sensor replacement cost.
I'm not sure how useful or necessary pH meters are for the average coffeegeek. But for the record, this pH meter has lasted me for six or seven years and is still going strong.
If you want it to be accurate and to last, I believe you need to buy four liquids and always have them on hand:
distilled water for rinsing
pH 4.0 calibration solution
pH 7.0 calibration solution
sensor storage solution (for my probe the manufacturer's recommended solution is ~ pH 5.8, not 7.0)
If you handle it with reasonable care and always keep the probe wet with storage solution, I think a decent meter and sensor will last a long time. If the sensor dries out, you may need to buy a new one.
Posted Sat Jun 9, 2012, 11:26pm Subject: Re: For those who measure their water, what TDS and pH meters do you use?
How much better (for our purposes) is a pH meter as opposed to the test strips?
I was just experimenting with my ohm meter set to a really high range and with the two probes set a specific distance apart. I can easily see a different resistance (measuring conductivity of the water) between distilled, RO and filtered tap water. The actual numbers don't mean much to me but being able to see the difference is kind of useful. But I suppose a real TDS meter would be a lot cooler (?) or is that the same principle it uses? (sorry in advance if that's a really dumb question - I have zero experience with TDS meters - really just experimenting with taste differences between different types of water so far)
These various test methods do not necessarily measure the same variables. My personal opinions:
Water hardness test strips are dirt cheap and good for monitoring your water hardness.
An inexpensive TDS meter ($50-$100) is accurate enough to be worthwhile for monitoring your water dissolved solids.
Decent pH meters are fairly expensive ($200+), require care and feeding, and are unlikely to improve your coffee.
A coffee refractometer is relatively expensive ($400-$800) but will quickly give you information on coffee TDS and extraction yield that would be difficult and/or tedious to gather by other means.
Posted Sun Jun 10, 2012, 9:43am Subject: Re: For those who measure their water, what TDS and pH meters do you use?
andys Said:
These various test methods do not necessarily measure the same variables. My personal opinions:
Water hardness test strips are dirt cheap and good for monitoring your water hardness.
An inexpensive TDS meter ($50-$100) is accurate enough to be worthwhile for monitoring your water dissolved solids.
Decent pH meters are fairly expensive ($200+), require care and feeding, and are unlikely to improve your coffee.
A coffee refractometer is relatively expensive ($400-$800) but will quickly give you information on coffee TDS and extraction yield that would be difficult and/or tedious to gather by other means.
TDS will not be useful for measuring coffee, just the water used to make it.
I find that the range of acceptable water is much larger than the range of strengths you achieve based on the brewing parameter (and by inference, extraction) that are "acceptable".
I know, I know, SCAA recommends specific water quality guidelines... but the bottom line for water is if you drink it straight and have no issues with it (i.e. it's water you fill your water bottle with and drink all the time, and it tastes fine to you) it will be absolutely fine for making coffee. If it's extremely hard (15+grains, 14+DH or >250ppm) you'll know because it leaves spots and calcium deposits on everything. The effects on taste are fairly subtle, compared to mis-brewing your coffee (by underdosing, or overdosing and underextracting, for example, or having tons of dust in the grind).
An example is my own water - distilled makes pretty brash and harsh coffee. My straight-on tap water is 255pph TDS, nearly all of which is calcium. The water I actually use is about 125ppm TDS, but since these solids come from calcium, the hardness is 7-8 DH (about 115 - 125ppm) - technically above the SCAA guidelines. But, the reason I set the water here is by experimenting with consistent brewing technique, and using hi/lo search to determine my own personal acceptable level of hardness/TDS (and others that participated in blind paired comparisons).
A water test kit (for General Hardness and Temporary Hardness/aka Alkalinity) is indeed cheap, and useful TDS meters will tell you just about everything you need to know about your brew water.
The extra added information for pH is only a nice-to-have, and IMHO is fine if you're spending $10 on a disposable-ish meter, but for me is not worth the extra $$ for the highly accurate ones. It's not like you test your coffee, find the pH higher than it was the last brew, and you're going to change something. You won't use your pH meter for adjusting the water quality (you're not going to add CaCO3 to bump up or neutralize water that's acidic, and you won't throw in a drop of HCl to adjust alkaline water or coffee), and you won't gain much useful information about the coffee because the acidity of coffee varies by brewing method and bean origin anyway.
Spend the couple hundred on a good grinder or save some more pennies to get yourself something more useful:
By far, the most useful device for tuning coffee brewing techniques is a coffee-calibrated, accurate refractometer. Knowing the strength of produced coffee is the most useful thing to know about coffee you just produced.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
UserNameGoesHere Senior Member Joined: 11 Dec 2006 Posts: 10 Location: San Diego Expertise: I love coffee
Posted Mon Jun 11, 2012, 12:57am Subject: Re: For those who measure their water, what TDS and pH meters do you use?
I might skip the pH stuff since there is nothing I can do about it. But is there a quality difference in the budget TDS meters I mentioned? I'm guessing no.
BTW, if you have an extra coffee refractometer on hand, I'll PM you my address.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
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