Temperature throws off sg readings?

[regulatedhobbyist]

I read somewhere that a higher temp of the must will affect your sg readings. I can't seem to find it now. Anyone have those numbers?

I'm putting together 7 lbs with 1.5 gallons water and getting an og of 1.131 at 95 degrees. Is this right? the FAQ says my OG should be 1.118.

Any thoughts?

 

[regulatedhobbyist]

Well, I shoved my pot outside for a couple of hours, and let it cool down. Came down to 75F. The gravity actually went up to 1.135! Who knew. Added some water, not sure how much. I just poured and mixed. There's about 1/4 to 1/3 gallon left in the jug. s.g. reading was at 1.114 which is right about where I wanted it. Meanwhile, the D47 starter I had was foaming well above my glass container lip. So I split my batch and my yeast, pitched, and here I am.

Any thoughts on how to recalc my volume? Maybe just measure out what was left in the jug and figure it that way?

 

[TomSD]

If you mean with a hydrometer you have to adjust your reading based on the temperature of the liquid you are measuring...

Here is a handy calculator that does it for you.

 

[regulatedhobbyist]

If you mean with a hydrometer you have to adjust your reading based on the temperature of the liquid you are measuring...

Here is a handy calculator that does it for you.

Bookmarked! Thank you! I do mean with a hydrometer. Thanks again.

 

[Onihige]

Hydrometers are calibrated to 15 °C

That is very low. Mine are calibrated for 20°c, any lower and I'd have to put my sample in the fridge before measuring.

 

[tweake]

I'm putting together 7 lbs with 1.5 gallons water and getting an og of 1.131 at 95 degrees. Is this right? the FAQ says my OG should be 1.118.

Any thoughts?

Well, I shoved my pot outside for a couple of hours, and let it cool down. Came down to 75F. The gravity actually went up to 1.135! ......

Any thoughts on how to recalc my volume? Maybe just measure out what was left in the jug and figure it that way?

you probably get more error in reading the gravity than the difference in temp causes.
your original problem is caused by honey varying in sugar content and your measurements are probably not all that accurate.
fine tuning by hydrometer is the best way to go. thats far far more accurate than doing it weights and volume.

 

[GinKings]

you probably get more error in reading the gravity than the difference in temp causes.

Not correcting for temp can cause a pretty big error if it's a big temperature difference. My hydrometer is calibrated to 60 degrees (15.56 C). If I measure a sample at 100 degrees, the correction is 6 points. That would throw off my ABV calcs by almost 1% ABV.

 

[tweake]

Not correcting for temp can cause a pretty big error if it's a big temperature difference. My hydrometer is calibrated to 60 degrees (15.56 C). If I measure a sample at 100 degrees, the correction is 6 points. That would throw off my ABV calcs by almost 1% ABV.

most people would be lucky to read a hydrometer to +/-5 points anyway.
add in bubbles, co2 etc 10 points out is nothing.
1% error due to temp is not much overall.

still a hydrometer is far more accurate than doing it by weight and volume.

 

[regulatedhobbyist]

most people would be lucky to read a hydrometer to +/-5 points anyway.
add in bubbles, co2 etc 10 points out is nothing.
1% error due to temp is not much overall.

still a hydrometer is far more accurate than doing it by weight and volume.

Well, For the record, I do know how to read a hydrometer. Thank you for your concern. However, The temp was 95 witha reading of 1.131. as the temp cooled the SG went up. I was more concerned about the sg in the first place. I was trying to figure out why according to the calculations from the Hightest supplied honey spreadsheet in the FAQ suggested I had a SG of 1.118. I ended up just letting the batch cool until it was 65 F and then added water until it was at the sg I wanted. ended up with 1.114 (and yes I triple checked it)

 

[tweake]

I was trying to figure out why according to the calculations from the Hightest supplied honey spreadsheet in the FAQ suggested I had a SG of 1.118.

not uncommon. honey varies in sugar level and measuring of honey and water is not exactly accurate.

I ended up just letting the batch cool until it was 65 F and then added water until it was at the sg I wanted. ended up with 1.114 (and yes I triple checked it)

that absolutely perfect.
get the rough amount of honey and water, then fine tune with hydrometer.