refractometer
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MmmBeer
Brew Pub Brewer
I bought a refractometer from ebay for about £4. It gets calibrated monthly using distilled water (condensed steam from the kettle) and uses 1 or 2 ml of wort to take an OG reading and is a very quick and simple reading.
However, they should not be used after the brewday to measure the gravity of beer. Once there is alcohol in the mix, you have to rely on your hydrometer and dispose of or preferably imbibe the liquid from your sample jar.
However, they should not be used after the brewday to measure the gravity of beer. Once there is alcohol in the mix, you have to rely on your hydrometer and dispose of or preferably imbibe the liquid from your sample jar.
Drunkula
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I got a really cheap refractometer and it reads the same with tap or distilled water. The thing to using them is if you give them a swill in water and even a wipe then some moisture can remain. Same with wort from an earlier sample. Because you're using such tiny amounts previous samples can mix with the new one.
* Run the wort to be tested over the screen enough that it'll wash away any water and do the same with the screen. Especially the top screen as it can store more of the previous sample. I just dunk the whole head and screen in the wort if it's before the boil or during.
* As you close the screen do it in a way that pushes any bubbles away, flick it a few times if you have to. Bubbles make the image blurrier. I tilt it slightly upwards to help the bubbles move in the right direction as I slowly close the screen. It's a bit like putting a phone screen protector on - keep that line straight.
* Close the window as soon as you've got the sample - don't let it cool on a spoon because evaporation will make the wort more concentrated. Errors are due to the sample changing, not the tool. Take a few readings with the same wort until you're confident.
* Loads of them say "ATC" for auto temp correction but it's tripe - just let it cool but with the window closed. It won't take long.
You really can get great results with a cheap refractometer but they just don't tell you how to use it.
* Run the wort to be tested over the screen enough that it'll wash away any water and do the same with the screen. Especially the top screen as it can store more of the previous sample. I just dunk the whole head and screen in the wort if it's before the boil or during.
* As you close the screen do it in a way that pushes any bubbles away, flick it a few times if you have to. Bubbles make the image blurrier. I tilt it slightly upwards to help the bubbles move in the right direction as I slowly close the screen. It's a bit like putting a phone screen protector on - keep that line straight.
* Close the window as soon as you've got the sample - don't let it cool on a spoon because evaporation will make the wort more concentrated. Errors are due to the sample changing, not the tool. Take a few readings with the same wort until you're confident.
* Loads of them say "ATC" for auto temp correction but it's tripe - just let it cool but with the window closed. It won't take long.
You really can get great results with a cheap refractometer but they just don't tell you how to use it.
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