Calibrate Refractometer with purified water?

Can I calibrate my new refractometer with purified water and get good result? Or do I need to go and get some distilled water?

hinke said:

Can I calibrate my new refractometer with purified water and get good result? Or do I need to go and get some distilled water?

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Use the water you brew with.

Aha. Makes sense.

Thanks

Bsquared said:

Use the water you brew with.

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hinke said:

Aha. Makes sense.

Thanks

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not true.

You want your refractometer to read 0.0 using distilled water.

Purified water will probably be fine. You don't want the water to throw off the calibration so far that it's effecting your reading. I suppose it depends on how purified, but, I would think, it's a matter of close enough. If I use distilled water to calibrate and then measure water out of my water purifier, the reading is about the same.

I'll just pick up some distilled water then.

I ended up with one that is 0-40 brix atc. They ran out of the 0-32, so I got this one for the same price, $26.

My brew water reads 0.0005 (half a gravity point) higher than distilled water on my hydrometer.
Both read exactly the same on the refractometer.

I don't bother to correct for it.
I'm not sure how much of the minerals end up in the trub anyway.

Well, the purified water (nestle), reads the same as regular tap water. I'll get some distilled water just to make sure it is calibrated completely.

Tap water, purified water, RO water and distilled water all read exactly the same on both my refractometer (zero) and my hydrometer (1.0000). I guess none of them contain much sugar.

My Portland tap water is nearly mineral free, so I just calibrate my hydrometer & my refractometer with the same tap water that I brew with.

However, I am curious about this theoretically.
I can certainly understand wanting instruments to be accurate (as well as precise) to a known standard, however, when I measure the RI or gravity, I want to measure the extract I added to the water, not the minerals in the base water.

Say that my tap water gives an RI of 0.2 with a refractometer calibrated with distilled water.
Would I then subtract 0.2 from all your RI readings to get the actual extract I've added? Would that be any different from just calibrating with the tap water at 0?

Yes, that's what I would do and it the effect would be the same as calibrating to zero with tap water. I would seek another water source or dilute with distilled if my tap water had enough stuff dissolved in it to register a reading on a refractometer.

AZ_IPA said:

not true.

You want your refractometer to read 0.0 using distilled water.

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Why, the water you start with is your 0 value, like tarring your scale. if it has a brix of 0.05 compared to distilled water, than all your readings will be 0.05 short of your true values.

hinke said:

Can I calibrate my new refractometer with purified water and get good result? Or do I need to go and get some distilled water?

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I'd use distilled water and don't buy it. Bring a cup of water in a sauce pan to boil and place a clean, cold lid on the pan. Count to 10, and you will have enough distilled water on the inside of the lid to do the calibration.

Bsquared said:

Why, the water you start with is your 0 value, like tarring your scale. if it has a brix of 0.05 compared to distilled water, than all your readings will be 0.05 short of your true values.

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because you're not tarring your scale.

The instrument is designed to read 0.0 with water that has nothing to refract any of the light (aka, distilled water).

http://www.grapestompers.com/articles/refractometer_use.asp

And who reads their brix reading to the hundreths anyway?

(meaning, yes, your tap water will "work" depending on how anal you want to be about getting a proper calibration. I'm more of a "good enough for me" type brewer, so I use the spring water that I brew with; but the purists would only calibrate their refracto's with distilled water).

rcrabb22 said:

I'd use distilled water and don't buy it. Bring a cup of water in a sauce pan to boil and place a clean, cold lid on the pan. Count to 10, and you will have enough distilled water on the inside of the lid to do the calibration.

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This is the idea I had and what led me to search out this thread in the first place. Glad to see someone else has already done this. I have fine water to brew with can't see buying a gallon of distilled water just for the couple of drops I need to calibrate my refracto. Thanks

Mudflap said:

This is the idea I had and what led me to search out this thread in the first place. Glad to see someone else has already done this. I have fine water to brew with can't see buying a gallon of distilled water just for the couple of drops I need to calibrate my refracto. Thanks

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You will not get distilled water at all, its about the contrary. The more you boil it, the more the minerals concentrate. You would need to recuperate the steam from the boil to get distilled water. We had a small distilled water machine at a golf club I was working at 20 years ago to fill the cart batteries. Worked like I’m saying. Trust me on this.

benoitdaviau said:

You will not get distilled water at all, its about the contrary. The more you boil it, the more the minerals concentrate. You would need to recuperate the steam from the boil to get distilled water. We had a small distilled water machine at a golf club I was working at 20 years ago to fill the cart batteries. Worked like I’m saying. Trust me on this.

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I don't think OP means to boil the water down... the idea is to put the lid on, and the cup in the center of the pot. Then don't use the water that is sitting in the pot. Let it boil, steam condenses on the lid, then falls down into the "empty" cup. You only need a drop or two so this method would work, it just takes a really long time due to having to wait for "steam" from boiled water.

IMO... distilled water is cheap at the grocery store; $1 for a gallon... and you can put the lid back on the jug and re-use it.

Also, the diff between distilled water and RO water, or even tap water is likely negligible for this purpose. I used to calibrate with tap water all the time... next time you calibrate with distilled water throw some tap water on after and see if you can tell how much "higher" the SG reads than 0. In a perfect world your using distilled water, but for homebrew tap water may due just fine i a pinch.

I also don't think that answering a nine-year old post is going to help the OP much...