Perform a cognative function test. Run a set of pre determined mental and physical exersises with an inpartial and sober monitor taking measurements. Some will be measurable by either time, accuracy or other factor, some will have to be observational. Almost anything will do, but choose things that will log your deterioration over time. For example, Write a paragraph from memory on graph paper, recite some verse, do some mathematics, touch your nose while standing on one foot, draw a simple pre determined picture. The more tests the better the results to a point, but too many will take too long to perform. You can design the tests as you see fit, but appriciate that they need to reveal your intoxication, so something very easy sober maybe dfficult pissed. All factors about yourself that you can control should be the same as best you can. Empty stomach for n hours, similar ammounts of sleep and physical activity for the day etc. On the first day you need to base line yourself While sober. Run through all the tests, record the results then start drinking your commercial beer. You will perform the suite of tests at pre determined intervalls over the drinking session. Drinks should be measured and timed. On the night of the next test, drink home brew. Repeat the same measured drinking regieme. This will allow you to chart the difference. The most important thing is to keep every factor as close to the same as you can. Time of day, drinking environment, test timing, everything. You dont need mates over, you dont need music. Just drink the beer and measure. This way you can tell if the feelings you experience when drinking home brew are real or just a state of mind. If you find its your state of mind then all the better and rejoice in your home brew magic.