Buffs from food/drink stack! So you can drink brandy two or three times and you end up with a massive mind bar. Of course you have to wait until the drink/food meters go down so you can drink more, but if you get a brandy with a fill of 49 that means you can take two gulps right away and then keep trying every 10 or 15 mins to drink more and end up with a stupidly large mind bar. Of course this also means with increased brandy consumption you might die with liver failure but you only live once right? :D
I would only take two shots of brandy (with 50 filling or less) and wait till it's run out or about to run out before taking more. If you keep topping it up as soon as you can you will end up with a huge mind buff but you could end up later with the equivalent of only one shot of brandy on your stats but are unable to drink more because of a full stomach.
Of course Brandy does stack with a mind buff too and there are always entertainers in Mos Eisley cantina willing to buff your mind.