How long has Tweek known that there was meth in the coffee?

MommaTweek
Go follow her she's amazing!

Tweek:..Well I didn't completely figure out til' they started sending me to go get special 'Coffee Grinds' From Kenny's garage. The way the people looked. After a couple trips I realized what was actually going on. And it got me even more anxious figuring out that what we were doing was illegal.

Amber: Wow, that was straightforward. No stuttering. No yelling. Wow.

Tweek: What're you- Ack! Talking about?

Amber: Aaaand we're back! So thanks for reading! Bye-

Craig: Wait, Meth?

Amber: OOOOOOF

Tweek: Oh! Uh, yeah. It's nothing really-

Craig: No it's a lot actually! They've been giving you Meth?

Tweek: Well, yeah..

Craig: And you've figured it out and you continue drinking it!?

Tweek: What else should I do?!

Craig: I don't know? Stop drinking it!

Tweek: Coffee's addicting!

Craig: Get Coffee from the store!

Tweek: That be a disgrace to the coffee house!

Craig: You mean to the Meth House!

Tweek: You know, it's none of your fucking business!

Craig: You just told a stranger about it!-

Amber: OKAY GUYS! THANKS FOR READING BYE BYE FWENDS!