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What
is a Hydrometer? |
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A
Hydrometer is a scientific instrument which measures the density of
a liquid in relation to water (water being 1.000 on the Specific Gravity
Scale). In the Brewing Industry, this instrument allows us to
predict and finally measure the alcohol content of the beverage being
made. Like many scientific processes, using a Hydrometer requires
careful steps to insure accurate results. The steps involved
are not difficult but do require concentration and consistency. |
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Using
the Hydrometer... |
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Place
a sample of the liquid to be tested in the testing jar and gently
lower the Hydrometer into the sample. Spin the Hydrometer until
no air bubbles cling to the exterior of the instrument. Once
the Hydrometer stops moving, take the "Original Gravity Reading"
(before fermentation) on the Specific Gravity Scale. Be sure
to take the reading according to the "True Reading" principle
as shown in Figure 1. Use the "Original Gravity Reading"
is accurate. Record the Results. Once the beer or wine
has fermented, it is now time to take the "Final Gravity Reading".
To do this, repeat all previous steps and Record the Results.
Using the following equation, the alcohol content of the beer
or wine can be calculated. |
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Figure
1 |
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(Original Gravity Reading")
- (Final Gravity Reading") x (131) = % Alcohol Content |
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Temperature
Correction Chart |
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This hydrometer has been
calibrated to give a 100% accurate reading at 60 degrees F. This
means that if the temperature of the liquid being tested is other
than 60 degrees F, the Temperature Correction Chart below must be
used to obtain and accurate reading. |
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| Temperature
in
degrees F. |
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50
60
70
77
84
95
105 |
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Specific Gravity
Correction
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.005
No Correction
Add .001
Add .002
Add .003
Add .005
Add .007 |
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| Correction
Example
If the temperature of the "Wort" or "Must"
is 84 degrees F. and the Specific Gravity is 1.040, the true
reading would be: |
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The Specific Gravity
= 1.040
The Correction Figure = +.003
1.043
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Helpful Hints- |
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Cleanliness
It is extremely important to be sure that the Hydrometer is clean
and free of any dirt or debris. Be sure to sanitize the Hydrometer
and test the jar after every use. Once the reading has been
taken, it is best to discard tested liquid rather than risk contamination
of the beer of wine. |
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Temperature
Since liquids become less dense at higher temperatures
and more dense at lower temperatures, it is important to be consistent
with the temperature corrections. Please refer to the chart
on this page for more details. |
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Instruments * 1315 Pottsville St.* Lykens, PA 17048 * 717-453-7171
* Fax: 717-453-7179 |
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