Refractometer vs hydrometer

[Fal]

So with Sterling being cheap and homebrew on tap I bought a cheap refractometer from amazon. 

But after calibrating it I get totally different readings from my hydrometer with beer.

I calibrated them both with tap water and they both read 1.000 but with my beer the hydrometer reads 1.010 and the refractometer reads 1.020. Which do I believe? Is my new cheap refractometer sh1t?

[delzep]

Pretty sure that a refractometer should only be used before adding yeast as the alcohol throws the results, so use it for pre boil gravity and original gravity

[Dr Horrible]

The alcohol does affect the refractive index, but you can convert the reading for a fermented beer if you know what the starting gravity was.  There's a conversion calculator on Beersmith if you have it, probably many others online as well.

[Fal]

Aaaah I didn't know that. I just plugged the info into beersmith and I got similar results to my hydrometer. Thanks guys.

[Gerryjo]

So with Sterling being cheap and homebrew on tap I bought a cheap refractometer from amazon. 

But after calibrating it I get totally different readings from my hydrometer with beer.

I calibrated them both with tap water and they both read 1.000 but with my beer the hydrometer reads 1.010 and the refractometer reads 1.020. Which do I believe? Is my new cheap refractometer sh1t?

I got caught by relying on the refractometer and thought I had a stuck fermentation and chucked three different yeasts into it then after doing some research used the hydrometer to find it had finished all along.

Sent from my ALE-L21 using Tapatalk

[Fal]

Well as it happened I was ready to pitch a second yeast thinking it was stuck myself when I though 'I'll just put a message on the forum first'  We'll worth being hassled by Ciderhead to become a full member