Budweiser has their own malting plants where they produce a good percentage of the malt they use. I know for a fact that they also buy malt from Rahr regularly.
Are you trying to brew an American lager or just curious? Some say the differences between Miller/Bud/Coors and Pabst are subtle, but to me each beer stands out. Miller has a sulphur component that stands out, Bud and Coors are closer, both have a red apple character, Pabst has more malt character and is the cleanest of all of them. Now others may disagree with this, but buy a six pack of each in cans as fresh as you can get them and do a side by side. It's remarkable how different each of these beers are, at least to me.
I brew American lager and compete with it. I'm usually pretty successful. The best advice I can give is to try brewing it with both American yeast such as 2007 and then try with German yeast like 34/70 or even 833. I prefer German yeast. If hold back on the malt character and use 833, it comes out like Pabst. The best malt I've found for American lager is Rahr Premium Pilsner.
That's my 2 cents
i promise you, i am not being dismissive. but im interested in your apparent seriousness regarding american (adjunct?) lager, what is the appeal? Why? Any interesting things youve learned about it?
I first brewed it for my wife, she bet me I couldn’t brew a beer she liked. I’m an experienced brewer and I took her up on that bet.
It is one of the hardest beers to brew, only a Helles or Pilsner are as tough to get it right, at least to me Like all beers, it easy to brew, but to get it right is tough. I started competing with it after about 2 years of trying. I started winning regularly with it. It led me into German beers and has made me a better brewer. I brew mostly lagers now.
A decent American lager is really quite good. Over the years the I learned the judges prefer a very clean malt profile, very few esters and crisp finish. It wins every time and it’s delicious. No apple or sulfur, I use German yeast to reduce the apple character.
As far as when brewers started adding adjuncts, that goes back over 120 years. The German brewers added rice and corn to the malt bill to mimic the two row available in Europe. In North American only 6 row was widely available. 6 row had more diastatic power than 2 row and they took advantage of it to lighten the flavor of 6 row.