Refractometer Question?

[Azorean Brewer]

How do you properly use a refractometer. Readings, calculations etc ... And is there only one type? or do you have to specify one for alcohol ... I have seen them in manufacturing for measuring water soluable coolant concentrations, is this the same type that you would use for beer?.

Thanks in advance

Paul.

[jayhawk]

I actually just used one in Biology class the other day to measure salinity in sea water. It had a scale for salinity, and water density, which is what we brewers care about. Think of a binocular, but forget about the "bi" part, because a refractometer only has one ocular(?)to look in to. You place a small sample of liquid one the one end, and then just peer through the other to get a reading. When you look inside, there is a scale that appears with gravity levels (think of the scale on a hydrometer), and there is a colour change in the background at the point where the density reading should be taken. Hope that explains it. Surely there must be a few different models, but this is the one I used.

Chris

[Sisu]

This month's (11/03) BYO magazine has a great article on refractometers. They discuss different types, costs/benefits, and why they recommend having one on hand. Next month, they may have that article available on-line for free @ www.byo.com.