Would suspended co2 cause the specific gravity to be higher? I took a reading at 1.15 after a month in the fermentation Carboy. It tasted dry and done. There was enough co2 to bubble out once I but the racking stick in. Any thoughts?
specific gravity
- Thread starter Randzor
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My thoughts are no, it won't change the specific gravity. But I'm sure there's a chemist lurking out there with the exact answer.
ianw58
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The CO2 bubbles will adhere to the hydrometer and float it higher, making the apparent gravity seem higher than it is.
You can put your sample in a glass and shake it/stir it to knock the CO2 bubbles out of the sample.
Also, spin the hydrometer to knock bubbles off it, too.
You can put your sample in a glass and shake it/stir it to knock the CO2 bubbles out of the sample.
Also, spin the hydrometer to knock bubbles off it, too.
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It's probably the alcohol. Alcohol has a different refractive index than water, and will give higher readings when present in a solution than if the solution was only sugar water.
ianw58
Well-Known Member
There are some calculators on line that attempt to compensate for alcohol, but, because the soup that is beer is so complex, they're approximations at best. A hydrometer is the most reliable for fermenting wort.
That being said, the refractometer reading will be high.
That being said, the refractometer reading will be high.
It's the tool. Alcohol skews the reading, and it is inaccurate because the light refracts differently through alcohol vs through a sucrose solution.
It's useless to take a refractometer reading if you want to know the SG of fermenting/fermented products.
Thanks Yooper. So for learning sake, My initial reading is good, in the sense that it gives my ABV after calculations and the like, and the final reading is pretty worthless due to the alcohol refracting... Atleast cider ferments dry
Thanks Yooper. So for learning sake, My initial reading is good, in the sense that it gives my ABV after calculations and the like, and the final reading is pretty worthless due to the alcohol refracting... Atleast cider ferments dry
Yes, in general.
You can also tell when fermentation is finished, although not with an accurate reading. For example, say today's reading is 4 brix (it's not correct, but that's what it reads). If it's still at 4 brix next week, it's not changing. That's when you can pull a sample for a hydrometer reading just to make sure it's finished (and not stuck). It will start to clear pretty well when it finishes as well.
Some yeast strains will finish lower than others. I've had some ciders finish at .990 with wine yeast, and some at 1.004 or thereabouts with ale yeast. Still pretty dry, but not as bone dry as .990!
I use Champagne yeast, and wait a month till even looking at bottling. I tend to assume it finishes by that time, due to the strand and how long its been. I also watch the fermentation to make sure it was vigorous. I was just astounded last night as I was bottling that I was getting the reading that I was getting, while it tasted great and dry. I am fearful of bottle bombs so I came here to ask. Thank you for the great information.
