Refractometers

JD_19616

Hello ChefSteps,

Refractometers. I understand their basic function and how to use them, however I'm left with a question. First, since they function by measuring the refractive index of a liquid, does the liquid need to be completely clear in order to get an accurate reading? I'm assuming this isn't the case since I've seen people use them to measure the brix of tomato and fruit purees, however I'm curious as to whether or not suspended solids (as opposed to dissolved solids) impact the measurement. 

My main use for a refractometer would be to make fruit purees. My hope is that I can blend up any fresh fruit I have on hand and get an accurate measurement of the sugar content for use in ice creams and sorbets. 

Any insight would be greatly appreciated! Thanks.

- JD

rutjens

Hi JD,

As you probably know Brix would reflect the amount of sucrose in solution in water. Any other substance will interfere with your measurement. Since you're interested in sugar levels (mainly sucrose) I would advice you to make sure you reach maximum solubility and filter your solution. In that way you will approximate the reference sucrose/water solution as much as possible (and necessary in this case) and make your measurement more accurate. When measuring sugar content of your purees and if you want to include the filtered solids in your final product you have to make sure you measure/weigh everything. In that way you can calculate the amount of sugar/weight of purée.

Cheers,

Bas