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⇤ ← Revision 1 as of 2012-11-05 23:04:53
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| Original gravity: 1.088 at 76 °F (24.4 °C). Equivalent at 15 °C: 1.090 (+0.002). Measured 23 October 17:30. | Specific gravity is the ratio of densities of a liquid and a reference liquid. With water as a reference liquid (normally the case in brewing), water has an SG of 1.000; a liquid with an SG of 1.500 is 50% more dense than water, 2.000 is twice as dense, and so on. Unfermented wort has a higher SG than water, and ethanol has a lower SG than water, so when brewing beer, SG starts high and decreases as fermentation proceeds. |
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| All readings below at 70 °F (21.1 °C) | SG measurements are temperature-dependent; [[http://www.howtobrew.com/appendices/appendixA.html|John Palmer's table]] was used to adjust the measurements. |
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| To get the equivalent at 15 °C, add 0.001 | To convert SG to percent alcohol by volume, let ''o'' be the original gravity and ''f'' be the final gravity; then 131*(''o''-''f'') is the percent alcohol by volume. For our beer, for example, at the last measurement the saison-yeast beer was at ~3.6% ABV and the ESB at ~8.2% ABV. Original gravity: 1.088 at 76 °F (24.4 °C). Equivalent SG at 15 °C: 1.090 (+0.002). Measured 2012-10-23 17:00. All readings below at 70 °F (21.1 °C). To get the equivalent SG at 15 °C, add 0.001. |
Information regarding a brewing experiment conducted by NCSU statistics students in Fall 2012.
Data
Specific gravity is the ratio of densities of a liquid and a reference liquid. With water as a reference liquid (normally the case in brewing), water has an SG of 1.000; a liquid with an SG of 1.500 is 50% more dense than water, 2.000 is twice as dense, and so on. Unfermented wort has a higher SG than water, and ethanol has a lower SG than water, so when brewing beer, SG starts high and decreases as fermentation proceeds.
SG measurements are temperature-dependent; John Palmer's table was used to adjust the measurements.
To convert SG to percent alcohol by volume, let o be the original gravity and f be the final gravity; then 131*(o-f) is the percent alcohol by volume. For our beer, for example, at the last measurement the saison-yeast beer was at ~3.6% ABV and the ESB at ~8.2% ABV.
Original gravity: 1.088 at 76 °F (24.4 °C). Equivalent SG at 15 °C: 1.090 (+0.002). Measured 2012-10-23 17:00.
All readings below at 70 °F (21.1 °C). To get the equivalent SG at 15 °C, add 0.001.
2012-10-28 21:30
ESB: 1.050, 1.046, 1.032, 1.046
Saison: 1.070, 1.070, 1.070, 1.071
Adjusted:
ESB: 1.051, 1.047, 1.033, 1.047
Saison: 1.071, 1.071, 1.071, 1.072
2012-11-01 24:00
ESB: 1.035, 1.025, 1.030, 1.039
Saison: 1.063, 1.060, 1.065, 1.064
Adjusted:
ESB: 1.036, 1.026, 1.031, 1.040
Saison: 1.064, 1.061, 1.066, 1.065
2012-11-04 24:00
ESB: 1.025, 1.030, 1.026, 1.026
Saison: 1.062, 1.062, 1.063, 1.060
Adjusted:
ESB: 1.026, 1.031, 1.027, 1.027
Saison: 1.063, 1.063, 1.064, 1.061
