Drinking a large amount of (weak) cold-brew green tea gave me an almost euphoric feeling.

I made cold-brew green tea by putting 5 teabags in about 8 cups of water and just letting it soak overnight.

I consumed about 5 cups of it during the day. So at 30mg caffeine per teabag that's (5*30)/8*5 that's about 93mg caffeine, about the same as a cup of coffee and this was consumed over the course of an entire day.

It's worth trying if anyone's interested. Good healthy soda replacement as long as you don't add too much sugar.