Does alcohol improve chess performance or destroy it?

Caffeine + alcohol + loud music seems to help my blitz. Not only do I become very focused, but I trust my instinct and don't fear bad moves or losing material (or losing the game).

I guess I mean, I don't 2nd guess and recalculate stuff... is that good? In short time control blitz maybe it is, at least sometimes.

I've stopped eating pizza for lunch during chess tournaments. A glass of wine and a piece of fish, on the other hand ...

Alcohol improves your perception of how you are playing, and makes losing less painful. 

But objectively, of course alcohol is a serious impediment to chess improvement. 

Some people won't care about what's objective tho. 

Alekhine and Tal were both serious winos. And they became World Champions..

Max Euwe was interviewed by Pal Benko. Here is one exchange, regarding the 1935 world championship match:

Benko: I have heard many rumors that Alekhine was drinking heavily during the match and was behaving strangely sometimes.  Can you comment?

Euwe: I don’t think he was drinking more then than he usually did.  Of course he could drink as much as he wanted: at his hotel it was all free.  The owner of the Carlton Hotel, where he stayed, was a member of the Euwe Committee, but it was a natural courtesy to the illustrious guest that he should not be asked to pay for his drinks.  I think it helps to drink a little, but not in the long run.  I regretted not having drunk at all during the second match with Alekhine.

http://www.chesshistory.com/winter/extra/alekhinealcohol.html

lol play chess high...that's a different kind of evening...

Alcohol makes you think you are playing good moves - but when sober, you can see that they aren't.

These discussions always creep into the absurd because of folks who cannot distinguish moderate drinking from drunkenness. The quantity makes a critical difference. If you don't get that, keep your opinion to yourself because it is senseless.

 Quantity does make a difference. In college, I played a bunch of games with varying amounts of alcohol consumed.

Even one drink impairs chess judgement. I came to the conclusion that each beer was worth about 200 rating points in blitz. The more I drank, the less I cared about losing, and the better my bad sacs appeared. 

https://americanaddictioncenters.org/alcoholism-treatment/mental-effects/

I mean... this is going to depend from person to person.

I can't hardly feel any effects from one beer. Like... just a little more relaxed I guess.

But definitely there's a threshold, like @ziryab is saying, after which it's all downhill. For me that's probably around 3 drinks.

I agree that everyone is different, but alcohol affects nearly everyone, even when it's only one glass of beer. 

I don't feel the effect of one beer, but I can measure it. Watch some of those youtube videos on the effects of beer and you'll see that even one beer will slow down response time. Ok, if you weigh +300 lbs, perhaps it won't have as much of an effect. 

Yeah, I see what you're saying. No matter my experience of it, the chemistry that happens in my body is undeniable.

But still, I think some of blitz performance is a willingness or ability to concentrate. This is true even when sober. And the more often you're drunk (I drink about 5 times a week) the more you're able to... mimic sobriety. Yes it affects me, for sure, but I'm more experienced (than some) so I know better how to not give in to the sloppiness so to speak.

Because seriously, if it's 200 points for 1 beer, and I take 3 shots in 30 minutes, finish my meal, and then play at a 1900ish blitz level here, then I'm supposedly 2500 blitz here which I guarantee is 100% not going to happen without some massive cheating

And I weigh about 150lbs, so I'm not a giant or anything

But if I have 4 drinks with a meal, I'm usually struggling to get to 1700.

It's seriously better to just not drink at all.

I highly recommend it

yeah, even 3 glasses of wine I had before a round, it took the first hour of the 4 hour game for me to sober up.  It's very different in a tournament, but alcohol among social games are fun

The science is indeed clear. Response time and judgement are affected by alcohol. However, in the game of chess a slight slowing of unproductive mental processes can improve focus.

Ritalin (prescribed for ADHD) does the same, as does nicotine. 

I never measure prime cases, measure gunpowder, seat bullets, or shoot after even one drink.

I do find moderate use useful when playing blitz or for the early rounds of a Swiss tournament. Although I often have drinks at lunch on Saturday during a weekend Swiss, I avoid alcohol on Sundays until the last round is over.

I am a very light drinker. One beer does it for me for the evening. With me the one beer seems to even out. I tend to throw caution to the wind and im more aggressive than normal. My view is that i would never drink before (or during) a rated game but if it is non rated I might depending on the  circumstances.