Yet another complaint thread about a malfuntioning refractometer!!!

[Revvy]

Here's why it is considered the norm to use distilled over tap water- consitency.

Believe it or not it tool me a LONG time to find the answer on the intertetz. Everyone talks about the importance of calibrating with distilled, but almost no-where does it explain why.

Everybody's water is going to be different, everyone's plumbing is going to be different, we know from brewing that different regions have water with different mineral content- Like Burton on trent for instance. Even boiling different waters aren't going to make them all the same.

The idea is that distilled water is going to be the most consistant due to the process of distillation.

It's going to be the most purest and free of minerals.

Natural water usually contains a number of microscopic contaminants, along with dissolved minerals such as calcium and iron. One way to remove these elements from water is to boil it until it changes to steam, a process known as distillation. When this steam is allowed to cool down and condense into liquid form again, the result is a purified form called distilled water. Distilled water should ideally be nothing but hydrogen and oxygen molecules, with a PH level of 7 and no additional gases, minerals or contaminants.

The distilling process relies on the principle that most solid materials found in water are heavier than the water molecules themselves. When water is heated in a distiller, any dissolved solids such as salt, bacteria, calcium or iron remain solid while the pure water converts to a much lighter steam and is drawn out for condensation. Distilled water has a noticeably bland taste because all of the minerals which give water its flavor have been removed.

BUT if you start reading forums about fishtanks and such you'll see that the argument is not Tap water vs Distilled water, it's Calibration Fluid vs Distilled water.

In the case of a refractometer, the reference standard is generally a fluid that has been prepared or standardized on instrumentation that is traceable to a nationally or internationally recognized source; alternatively, it may be a fluid such as distilled water that has accepted physical properties. Traceability relates individual refractometer results through an unbroken chain of calibrations back to a national standard, a fundamental physical property, international standards, or a consensus standard. At MISCO, we provide traceability back to the U.S. National Institute of Standards and Technology (“NIST&#8221.

This is an interesting article about even the difference between cali fluid and distilled;

After doing a lot of research I came across endless debates online regarding zeroing a refractometer with ro/di water vs using calibration fluid. Both sides had good points: the scientific side said the only accurate measurement was with calibration fluid, and the general hobbyist side echoing what refractometer instructions say. Unfortunately it was the general hobbyist side that usually overwhelmed the debates, which made it seem like ro/di was the way to go. All I knew was that the refractometer was the only thing that had changed, and my tank was a disaster, so I decided it was time to test both sides of the argument.

I ordered this calibration fluid from Marine Depot, which was lab tested to make sure it was at nearly exactly 1.026. It wasn't easy seeing my tank go from bad to worse while I was waiting, fortunately though they're a local company and I had it the next day! I couldn't make it through my work day fast enough, my corals were dying and the cure might be sitting on my front porch.

When I finally got home I tore open the box and ran over to test the refractometer. As I peeked in my first reaction was, in all honesty, "wow, this calibration fluid is broken." It actually took me a few minutes to come to the realization they my calibration fluid was not broken. I'd figured the refractometer would be off by .001, maybe .002. Instead I was looking at a reading of 1.030. Was it true? Even after being zeroed out with distilled water like the instructions said, could it really have been reading .004 too high? Unfortunately, yes.

Granted with fish it's life and death, and a few points difference in gravity of out beer isn't going to probably be all that different, even between tap and distilled...BUT hopefully now you can see why distilled is the hobby norm for calibration.

You basically want to zero out your test device, and you want to know it is zero, or whatever the calibration standard is. It's like check the accuracy of a scale in the old days with a standard weight set. You want to trust that a gram is really a gram, before you measure whatever is important to you.

 

[Orthobrewsky]

Here's why it is considered the norm to use distilled over tap water- consitency.

Believe it or not it tool me a LONG time to find the answer on the intertetz. Everyone talks about the importance of calibrating with distilled, but almost no-where does it explain why.

Everybody's water is going to be different, everyone's plumbing is going to be different, we know from brewing that different regions have water with different mineral content- Like Burton on trent for instance. Even boiling different waters aren't going to make them all the same.

This would explain why the factory sends these out calibrated with distilled water, but not why you would calibrate with distilled water. When you calibrate your device, you don't really care what the water is like in various parts of the world, but only with what your water is like today for your brew.

You basically want to zero out your test device, and you want to know it is zero, or whatever the calibration standard is. It's like check the accuracy of a scale in the old days with a standard weight set. You want to trust that a gram is really a gram, before you measure whatever is important to you.

To zero a scale, you don't need a standard weight set. Using a standard weight set to correct a scale would correspond to finding a correction factor for your refractometer when using it with wort as opposed to clear sugar water. Zeroing a scale would correspond to zeroing your refractometer.

From what I've heard, it doesn't sound like it makes much difference whether we use distilled or tap water. However, to the extent that it may make a difference, it certainly seems we should use the water with which we brew. Here's an analogy:

The scales we use to weigh our ingredients may arrive from the factory "zeroed." If so, they will calibrate zero by using no basket on top. The reason is for consistency. We all use different baskets to hold our ingredients together on the scale for weighing. However, I want my scale to read zero when my empty basket is on it. An empty basket is weight on the scale, but it is not what we want to measure, so we treat it as if its weight is zero, so that we get the weight of our ingredients. When it comes to using a refractometer to measure the sugars we place in our water, we want to measure those only. The tap water or spring water is only the "basket" we use to hold our extract. Even your hydrometer may not read zero if you have a lot of mineral content in your water. To find our how much sugar you have dissolved in that same high mineral water, you'd want to zero your hydrometer (not normally possible except by subtraction) to the high mineral water not to distilled water.

A mathematical proof:
Specific gravity minus 1 is a linear function of the ingredients we put in our wort. The vertical intercept of that linear function is zero--the equation is of the form y = mx. If we put in 3 times as much extract, we expect 3 times the number of gravity points. As I understand it, Brix is not precisely a linear function, with vertical intercept zero, of specific gravity since the conversion formula is not as simple as y = mx. However, it is extremely close to such a linear function. So much so that that I can't detect the difference between a standard conversion table and the formula y = 4x (x=brix and y=(SG-1)*1000, of course) until I reach a level in the neighborhood of SG=1.080 and then it is so close it is hard to care about the difference. Furthermore, even at that level and beyond, 4x hits below the true conversion, so (4 + very little)x would be an even closer linear function. Thus, since the function between brix and gravity points is (almost precisely) linear with vertical intercept zero, and the function between gravity points and dissolved sugars is linear with vertical intercept zero, the composition of these two linear functions is (almost precisely) linear with with vertical intercept zero. Given that what we wish to measure is dissolved sugar (not mineral content), we should zero our refractometers with our brewing water rather than with distilled water.

 

[Spartan1979]

There also is the question of how accurate the hydrometer is. Mine reads .002 high.

 

[wolfman_48442]

Any suggestions on how to not get debris in there because that seems pretty hard to do wig all the hops and everything else.

With mine, I use a turkey baster to take more than I need for the sample and drop it in a clean shot glass. Then I let all the bits of stuff settle down, cool, etc and then take my reading. I then have a bit left over for a taste sample.

Average of three readings since I usually forget something and will get at least 1 wack reading...

 

[mattd2]

...Also I used a pipette but when u put the few drops on the glass...you can see there were a few bits of particulate matter.... probably hop material. I'm still confused.

I get a little bit of partical matter in my samples too, I put it down to hop/break material. From what I have read it might affect the sharpness of the divide (it will be more fuzzy) but not the actual reading as it is a solid suspended in the liquid and therfore not changing the liquids properties. Of coarse I could have read it wrong

 

[ajf]

Here's why it is considered the norm to use distilled over tap water- consitency.

Believe it or not it tool me a LONG time to find the answer on the intertetz. Everyone talks about the importance of calibrating with distilled, but almost no-where does it explain why.

Everybody's water is going to be different, everyone's plumbing is going to be different, we know from brewing that different regions have water with different mineral content- Like Burton on trent for instance. Even boiling different waters aren't going to make them all the same.

The idea is that distilled water is going to be the most consistant due to the process of distillation.

I think that makes a good case for using tap water to calibrate instruments when brewing. For most waters, I don't think there will be a measurable difference between tap and distilled water when using an hydrometer to take the measurements, but let's say that distilled water reads 1.000 and tap water reads 1.002.
Now suppose you make two identical brews, one with distilled water, and one with tap water. The brew made with the tap water will have an OG and FG 2 points higher than the distilled water brew (assuming they were identical except for the source of the water).
If you calibrated your hydrometer is distilled water, then all of your readings will read 2 points high, but if you calibrated it tap water, then the readings would automatically correct for the higher density of the tap water. Brewers are interested in the amount that the gravity increases from a know starting point.
In the case of aquariums, the fish don't give a damn about the density of the water, but they care very much about the dissolved solids, so in that case you do want your instruments calibrated against a know and reliable standard. They want an absolute reading.

-a.

 

[wildwest450]

Refractometers should come with a tongue, then they could at least lick your balls.


_

 

[Orthobrewsky]

I broke down and got one (deeply on sale) after struggling with extracting hydrometer samples to see when a perpetually bubbling beer was really finished. So far as that part of things goes, I don't need to zero it and I don't need a correction factor. I just need to see that my brix reading, whatever that may really mean, has stopped moving. It's still a new toy and I envision taking a preboil hydrometer reading, computing a correction factor, (I may just throw the sample in the boil later) and a final hydrometer reading (there's always enough leftover for that when I bottle). So, what it can do for me is let me take instant readings during the boil to see what SG I'm getting to and during fermentation to see when I'm finished.

 

[Marquez]

Refractometers should come with a tongue, then they could at least lick your balls.


_

That's brewer's gold!

 

[Orthobrewsky]

That's brewer's gold!

There is something at the front end of it that pretty much moves like a tongue, but it doesn't move by itself. Still, it could be a nice feature.

 

[rico567]

And then, for some of us (the group "some of us" in this case is restricted to "me"), how much point on a pencil is enough? My refractometer, which I calibrate from time to time with the RO water that's always around, always reads 0.000. When I'm brewing and measure first runnings, or preboil, OG, etc. it always gives me the information I'm looking for, i.e., that the expected SG is (about, ± ) where I'd expect it to be, e.g, it's between OG 1.054 - 1.064. Most of this stuff is in ranges, not a specific number with 3 digits to the right of the decimal point that I MUST hit on the nose or I'm gonna have an unsatisfactory beer. That's all I want out of my refractometer, so I'm happy.

 

[Orthobrewsky]

I've had some experience with the device now and have found it useful and consistently pretty accurate for my "gravity of fermenting wort" when using the Beersmith refractometer tool. One oddity I've noticed is that I seem to get somewhat inflated values for preboil readings. I've wondered if it could have to do with the hot and cold break still being in solution. Anyone else notice this?

By the way, sorry about the "mathematical proof." It occurred to me later that only very strange people in a certain mood would find it entertaining due to its gratuitous overcomplication. Well, I was at "work"...