Specific Gravity During Fermentation

[cubbie]

I keep breaking my hydrometer so currently on using my refractometer.

I want to calculate my SG now that my fermentation is winding down. At the start of fermentation I had a gravity of 1.064 (16.8 Brix)

Then during fermentation I added and extra 18 gravity points of sugar to give me 1.084.

Question is how does that effect the refractometer reading? I am using Promash so do I just plug in 1.084 as my starting gravity or 1.064?

At 8.8brix which I took this morning I would have a Measured Apparent Attenuation of 94% which does not seem correct. at 1.064 it is 75%

Cheers.

 

[RobW]

You need this:


View attachment Refractometer_Chart___During_Fermentation___Brix_to_SG.xls

 

[raven19]

Ideally you have access to a spare (fellow brewers) hydrometer.

I just dont trust ANY of the online or spreadsheet tools for conversion - my refractometer gives me 'interesting' (albeit steady numbers) results during the ferment, and when converted back using beersmith and other tools, I get FG's of 1001/1003 when the hydrometer tells me 1008/1010.

However, regardless of the above, I would anticipate your Brix reading to drop to 7.5 ish still - assuming an FG of around 1010 ish.

* Your SG will be your measured SG (tweaked for this brews efficiency) plus the effect of the sugaz added to the wort, hence pump it all into Promash and use that calculated number. I had similar fun with gravity numbers during my recent Belgian Tripel with multiple sugaz additions during ferment...