If you not mind, another question. Can u give the 101 on how to use a hydrometer to test alcohol?
Yes...
If you have a test jar, fill the tube with wort and let the hydrometer float in the wort. Find the marked line that is touching the top of the wort when the hydrometer is floating.
If you do not have a test jar, then santitze the hydrometer thorougly, and float it directly in the fermentation jug. Again, you are looking for the number marking that is flush with the beer... Depending on your recipe, you will have a number somewhere between 1.030 and 1.080 in most cases. Some hydrometers also have a "potential alcohol" scale which may be easier to understand for new brewers. You can use the gravity number, or the potential alcohol, whichever you prefer...
Record your initial reading (O.G. or potential alcohol) and save that number for later. When the beer has been fermenting for at least one week (2 is better!), take a second reading. You should now have a reading that is much lower than the first number. Most extact batches finish between 1.008 and 1.020, and all grain beers can get very close to 1.000 depending on several variables. This is your final gravity (F.G) When the F.G. is the same for 3 days in a row, the beer is done and ready to bottle.
Once you have the "before" and "after" readings, you can use them to calculate the alcohol percentage. The book "How To Brew" by John Palmer has a chart in it for this (Get this book if you do not have it!) or you can use an online calculator to do the math for you. If you used the "potential alcohol" scale for testing, then simply subtract the finishing number from the starting number. For example, if the before reading was 6% potential alcohol, and the after reading was 2%, then your beer has 4% alcohol.
One last note: beer temperature affects hydrometer readings, and the reading should be corrected for temperature. Personally, I do not do this. I simply make sure that my before and after readings are taken at the SAME temperature (room temp, about 70 degrees). If one sample is hotter than the other, you will need to learn how to do temperature corrections...
I hope this has helped, rather than confused you worse!