How do I cook meth?

Solution 1:

Above is an image of the meth lab and where the specific ingredients are placed when cooking. Note that Mu = Muriatic Acid, Cs = Caustic Soda and Hcl = Hydrogen Chloride. (Image source: PAYDAY wiki, "Rats")

In multiplayer, the required ingredient is synchronized across all players, but the dialog from Bain is not.

Other notes:

• Be careful not to grab ingredients too quickly. If you interact with two ingredients of the same kind too fast, you get one ingredient for the price of two. Similarly, if two people add the same ingredient in the lab simultaneously, it will disappear from both inventories.
• Each ingredient is used only once for each bag of meth, but the order is different each time. There are ingredients for a maximum number of 7 meth bags.

^{Source: The Long Guide by Frankelstner - Rats Day 1 notes}
Bain has a number of lines where he's incorrect, though he will correct himself shortly afterwards and state the right ingredient. He also has a multitude of non-unique correct lines for what ingredient to put in.

Bain is wrong when he says:

• Now we need... I'm going with (ingredient). Hold up!
• Uh... mhm...We'll go with (ingredient). Nope, that's not it!
• Alright, next ingredient...(ingredient)? Sorry, that wasn't right.
• Alright, let's see...We'll go with (ingredient). Strike that.
• Hold on... I'm going with (ingredient). Wait a minute!

After saying one of the wrong lines, he corrects himself, saying the right ingredient:

• It's supposed to be (ingredient)! Pour it in.
• It's supposed to be (ingredient)! That should get the process going.
• I messed up. It should'a been (ingredient). That should get it on.
• I messed up. It should'a been (ingredient). Pour it in.
• We need (ingredient)!
• That should'a been (ingredient)! ...unless I've missed something...
• ...(ingredient)?...I'm XX% sure.
• By method of elimination it has to be (ingredient). ...what's the worst that could happen, right?
• My bad. It's (ingredient). Add some.

Bain is right when he says:

• Uh, I hope I got this right... (ingredient)? ...I'm XX% sure.
• Uh. I hope I got this right... (ingredient)? You got any of that lying around?
• Uh. I hope I got this right... We'll go with (ingredient). ...I...think.
• Okay, what's next... (ingredient)? ...I'm XX% sure.
• Okay, what's next... Oh I'm going with (ingredient). ...it's a toss-up, really.
• Okay, what comes after that... We'll go with (ingredient). That should get the process going.
• Okay, what comes after that... (ingredient). That should get the process going.
• Okay, what comes after that... It's (ingredient). That should get it on.
• Uh... mhm... It's (ingredient). ...that's my very best guess.
• Uh... mhm... (ingredient). ...this website better be accurate.
• Uh... mhm... (ingredient). That should get it on.
• Uh... mhm... (ingredient)? ...IF my calculations are correct.
• Uh... mhm... (ingredient)? ...and kiss your lucky charms.
• Uh... mhm... I'm going with (ingredient). Go for it.
• Alright, next ingredient... We'll go with (ingredient). That should get the process going.
• Alright, next ingredient... We'll go with (ingredient). ...I'm XX% sure.
• Alright, let's see... (ingredient). ...I think so, at least.
• Alright, let's see... (ingredient). ...I think so, at least.
• Alright, let's see... (ingredient)? ...yeah... yeah.
• Alright, let's see... (ingredient)? ...I'm XX% sure.
• Alright, let's see... It's (ingredient). ...unless I've missed something...
• Uh, I hope I got this right... (ingredient)? You got any of that lying around?
• Uh, I hope I got this right... We'll go with (ingredient). ...for sure. Or, most likely.
• Now we need... It's (ingredient). ...that's my best guess.
• Now we need... We'll go with (ingredient). ...I'm XX% sure.
• Now we need... We'll go with (ingredient). ...what's the worst that could happen, right?
• Now we need... I'm going with (ingredient). ...these internet descriptions are iffy at best.
• Hold on... (ingredient). I'm XX% sure.
• Uh, if I read this correctly... uh... Oh I'm going with (ingredient). ...I'm XX% sure.

Wrong and right periods have a triple sentence structure. Each of the three sentences are randomly combined. The only reliable sentence that will reveal previous statement right or wrong is the last (i.e.: "...I'm 54% sure").

Correction periods have a double sentence structure. Both sentences will always reveal that the immediate information given is correct.

Examples of last sentences on false previous information:

• Hold up!
• Nope, that's not it!
• Sorry, that wasn't right.
• Strike that.
• Wait a minute!

Examples of last sentences on true previous information:

• ...I'm XX% sure.
• ...I...think.
• ...it's a toss-up, really.
• ...that's my very best guess.
• ...I think so, at least.
• ...this website better be accurate.
• ...IF my calculations are correct.
• ...and kiss your lucky charms.
• ...for sure. Or, most likely.
• ...yeah... yeah.
• ...unless I've missed something...
• ...what's the worst that could happen, right?
• ...these internet descriptions are iffy at best.
• Go for it.
• You got any of that lying around?
• That should get the process going.
• That should get it on.

^{Source: PAYDAY wiki, "Rats - Cooking"}

Solution 2:

There are 3 different ingredients: caustic soda, muriatic acid and hydrogen chloride. The order of which to use will be provided by Bain (your handler). Note that the information he gives initially can be wrong, so wait until he confirms that he is sure.

Each ingredient is placed on different parts/equipment in the lab, simply hover over different part of the lab to confirm what you are placing, this way you can be holding multiple ingredients and still apply the correct one.