Gravity reading question

You can measure gravity with a hydrometer at pretty much any temperature. Just make sure to correct the reading to the hydrometer's calibration temperature (usually printed on the hydrometer). Most brewing software should have the calculator for this. Or find a chart online.

ETA: If I were going to add DME or something to adjust gravity, I'd do it based on a pre-boil measurement.

 

Is there a standard 'do-not-exceed' temperature rating for hydrometers?
I'm not too swift on thermodynamics, but it seems like there could be some risk of cracking or breakage due to thermal shock if placing a glass hydrometer directly into super hot wort. Maybe acclimate/attemperate it a bit by running hot tap water over it first?

I usually add the sample to the jar and let it cool until it gets within about 15°F (or less) of the temperature the hydrometer is calibrated to.

I used a refractometer for the first time on my most recent batch and think I'm going to like it a lot once I determine my actual wort correction factor, or find out than the standard factor is close enough. It uses drops instead of ounces.

 

The wort correction factor is actually wort dependent, and not brewhouse dependent, if that's what you meant by "my." It's wort dependent because each type of sugar/dextrin has it's own refractive index.

Of course, if you tend to brew a lot of very similar beers, I guess you could have a standard factor that works well enough.

 

I’m not saying I’m correct in my method but I fill my test tube up and let it sit in my 5gallon bucket of Star San and water I keep beside the kettle. I usually put my spoon it when not stirring. I only fill the bucket up to 3/4 of the test tube and it cools it off fairly quick

 

During my first attempt at brewing (30+ years ago) I cracked my first hydrometer by trying to clean it in hot water. My guess is the metal weight expanded and the glass wasn't smart enough to do the same. I heard a distinct "tick" sound. From that time on I always wash with warm water and cool wort to near the calibration temp before taking a gravity reading, and correct for the temperature if needed.
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Yeah, seems risky to put a hydrometer in near boiling wort. I rarely bother checking pre boil gravity anymore. But when I do, I collect some wort in a gallon pitcher with some of those plastic ice things you throw in lunch bags. That will cool it to about 100F in minutes. You still need to adjust hydrometer reading for temperature though.

 

I’ve read where some folks say, “I figured my WCF to be 1.0X”. So that had me wondering when a deviation would be indicated, and how would one determine the appropriate factor?

Is the WCF used in BrewCipher automatically adjusted depending on one or more variables (expected attenuablity is mentioned in the hover-over note). Are there other considerations?

 

The recommended WCF is based on expected wort attenuability. (Nothing else.) Of course, users can override the recommended value and plug in 1.04 (or whatever).

 

Can you please explain the basis of this statement? Cheers!

 

Sean Terrill had found that the ideal WCF he needed to use for his calculator was related to the Apparent Degree of Attenuation (ADF) of the wort, which makes some intuitive sense, because various sugars and dextrins have different refractive indexes; it's the fact that wort is mostly not sucrose that makes WCFs necessary in the first place.

Sean found that a WCF of 1.04 was a good center for (his) worts with an average ADF of 81%, which I think is the zone in which he was mostly brewing. So, considering that a pure sucrose solution (with 122% ADF) would need no WCF at all (or alternately a WCF of 1.0), I simply used the formula for the slope of the line that passes through both of these datapoints, which is used for BrewCipher's default WCF recommendation.

IIRC, Sean found this interesting and certainly had no issues with me doing it. OTOH, I don't think he ever actually endorsed it either. I provided (hopefully) adequate disclaimers in the user manual and in the cell comments.

The next release of BC is actually going to cap the recommendation at 1.04, because I have found that when I get results that don't match my hydrometer very well, it tends to be the higher recommendations, and it's rare that anything above 1.04 is a great match. (It will still be able to be overridden by the user, or course.)