Hot answers tagged gravity-reading
You are absolutely correct. Unless something is dissolved into the liquid, or there's so much trub that the hydrometer is sitting on top of it, the reading will be unaffected.
Bottom line: its impossible for the gravity to decrease during boil. You only evaporate water, leaving an increasingly sugary solution. So there is an error with your preboil postboil or both gravity readings. Most common reasons for incorrect readings: Incomplete Mixings Failure to to a temperature adjustment Related to the second - Uncalibrated ...
Alcohol in fermented beer skews the refractometer reading. You need to use a correction formula in order to get an accurate reading.
Unless you added sugar or evaporated water, a misreading is the only answer I can come up with. Always make sure to spin your hydrometer to ensure there are no air bubbles forcing it up higher. Any chance your dog knocked in a pound of DME? :)
If the trub is actually physically holding the hydrometer up, preventing it from moving down, then unambiguously: yes, the trub will render your hydrometer reading useless. If, on the other hand, the trub is suspended in the liquid, it is a mixed bag. Suspended solids will impact a hydrometer reading, but for brewers it is usually very minimal. The only ...
I guess you're assuming the sample will continue to ferment with suspended yeast? There's quite a few reasons why this can fail: the sample may not be at the same temperature as the beer (both due to it's location plus it lacks the exothermic heat produced from the large volume of yeast in the main ferment.) the sample may become contaminated and ferment ...
I'd consider that within a reasonable margin of error. It will hardly affect your beer in a noticeable way. I wouldn't worry about it at all. In any case, that's pre boil. If you just boil a bit longer, you'll have slightly less beer but you'll be able to hit your intended OG. As to why it happened, there are any number of reasons for a minor thing like ...
Most likely user error with a small difference possible due to temperature and/or dissolved co2 floating the hydrometer. It's also possible that there is a density gradient, though it seems less likely after 2 weeks of fermenting.
Brewing tools like BeerSmith provide refractometer correction tools when taking readings of fermenting or fermented beer. You measure the SG of a given sample both with a hydrometer and a refractometer. This then allows you to determine the "skew factor" that is typical for you. You can then use this to correct subsequent refractometer readings. It's not ...
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