I have a cousin from a state where recreational use of marijuana is legal. So I've been told that he and his gnarly friends have brewed up some sort of marijuana hybrid beer somehow.
My questions:
I see the stoners on this as...
Going to drink some weed dude! Getting drunk and high at the same time, man!
'Is this possible that beer could be brewed up somehow with weed?'
Sure, in the same way you can put any sort of anything in your beers, as long as you think it will taste good. But to answer the more important question:
'[W]ould you get the effects of both beer and pot both?'
It would very much depend on how you used it in the process.
THC, the psychoactive chemical in marijuana, is barely soluble in water, 0.0028 mg/mL or 2.8 parts per million (according to Wikipedia). So if you added your herb to the boil, that's the most you could hope to get (a 20 liter batch of beer could be THC-saturated with just 0.6g of 10%-THC pot).
If you added it as a 'dry-herb' addition you would see a much higher solubility due to the presence of the alcohol formed during fermentation. THC is soluble in pure ethanol at 35 mg/mL (or 35,000 PPM)(source). Say your beer is 5% ABV and that's ~1,800 PPM it could contain. If my math is correct, that would take roughly 360g of 10%-TCH pot to fully saturate 20 liters, just about 9g. worth of potency you could hypothetically pack into each pint.
One key to this process you don't want to overlook (as noted in these instructions for making a tincture of marijuana) is that the psychoactivity of cannabis is dependent on heat-activaction of inert THCA to become active THC (when you smoke, vaporize, or bake the pot, this heat-activation is already part of the process). As outlined in the link, the herb must first be heated to cause this chemical change, but not so hot that it vaporizes the THC (225°F is recommended). If you skip this step before adding the herb, even if you are able to dissolve its chemicals, they may not be the ones you're after.
Since you'd have to add the herb post-fermentation anyway, this seems like the perfect kind of thing to experiment with using single bottles of beer, dosing and aging differently to see what works.
~EDIT~
Here's a thread on Reddit in which someone with some experience goes into more detail on the process.
And an older recipe from Erowid for marijuana beer.
Both mention another feasible way to add the pot to the beer, which I didn't consider. Basically you add it to the boil, as you would hops, and you make sure to transfer the entire contents of the kettle to the fermenter (hops, trub, everything you would normally leave behind) so that the THC-bearing plant material is in the fermenting beer as alcohol is produced.
The major bitter compound in hops, the so-called alpha acids, aka humulone, is a terpenoid (derived from terpenes). The primary active ingredient in that "herb" you're smoking, the tetrahydrocannabinoids, are also terpenoids.
Both Humulus lupulus (hops) and Cannabis sativa (marijuana) are, in fact, two genera in the family Cannabinaceae. It is entirely possible to graft one plant to the other...
As far as the effects, I'm sure something will come through with some experimentation.
Yes you can. Simular to cooking with it It can have all the medicinal effects.
There is a specific extraction that needs done, it's simple but I don't care to explain the how. As the question was only if it's possible.
It's not like a hop addition, or dry hopping. That will only make a skunk beer.
Another option is to make an ethanolic cannabis extract, then add it your brew.
Assuming you're seeking the psychoactive effects of weed, not just the unique aromas that are often associated with it,
Your process would look something like this:
The rest is up to you. There's a lot of experimentation to be done - try different amounts, different soaking periods, different baking methods.
Keep in mind:
This can also be done with adding nano emulsion of THC Distillate. I am currently making THC infused lemonade and teas using this method.
