Digital Refractometer for Brewing

This Hanna Instruments digital refractometer measures wort gravity on the scales brewers use.

Why it is measured

A refractometer needs two drops where a hydrometer needs a full cylinder, which is why it is the instrument used on the hot side: sparge, boil, knockout, all measured without pulling half a litre out of the brew.

Where it is used

• breweries and brewpubs
• sparge and boil control
• pre-fermentation gravity
• recipe development

How a refractometer works

Light bends by a different amount depending on how much is dissolved in a liquid. A refractometer measures that bend and converts it to a concentration scale. It needs one or two drops, gives an answer in seconds, and has no reagents and nothing to consume.

A digital instrument compensates for temperature automatically, which is the difference that matters: refractive index shifts with temperature enough that an uncompensated reading in a warm room is simply wrong.

Practical note

Once fermentation starts, alcohol distorts the refractive index; from that point a correction or a hydrometer is required.

Supplied as one model.