CA law is silent on alcohol and CCW. Therefore, it is legal. HOWEVER, and this is a big one, most issuing authorities add a stipulation on the license saying that you can't. Recently there was a case where a person, with a valid CCW license, defended himself with his gun, but didn't fire. Unfortunately for him, he had had a few drinks.
This is where it gets confusing...
There was a stipulation on his license saying he couldn't be under the influence of alcohol. Because he was drinking, this invalidated his license. Because his license was invalid, he was convicted of carrying a concealed weapon. The plea bargain netted him a 30 day suspended sentence and loss of his license.
So, technically, it's legal to drink and carry here in CA if your license doesn't have a stipulation against it because there is nothing in the penal code against it. Even so, I think it's extremely unwise to test this theory.
I don't/won't hang around people who drink. Therefore, this is not an issue for me. To the OP, I recommend not carrying any alcohol in the car while you're driving. That's my opinion, not a legal stance.
Have fun on your trip.