Editor's Note: This article was originally published at 7:45 a.m. EDT on Real Money on July 8. To see Jim Cramer's latest commentary as it's published, sign up for a free trial of Real Money.NEW YORK ( Real Money) -- Do yourself a favor. Don't listen to what Alcoa ( AA) earns. It won't be any good. There's always going to be too much aluminum, or too big a swing in some currency -- the Australian dollar? -- or too much capacity, or not enough shutdowns, or whatever. That's why this company is no longer considered a bellwether. It's a shame, though -- because it is, perhaps, underneath, the most important bellwether of all. That's because Alcoa is two companies. It is a maker of something that is in demand, but is too easy to make, and it is a global barometer of every single area that should be on fire if the rise in interest rates is right. That's important, because you hear, over and over again, that stocks go higher when rates rise -- but the question I always have is, "Which stocks?" After all, many will go down at the same time. What to listen for? First, because Alcoa has been furiously trying to close expensive capacity in Europe, we will want to know if CEO Klaus Kleinfeld sees a bottom developing. The stocks of huge aluminum users Ford Motor ( F) and General Motors ( GM) do, so perhaps Klaus will call it? He sure hasn't done so before. Second, what's really going on in China? Klaus will devote an entire section of his conference call's presentation to the future of China and to what the government's doing and can be doing on everything from pollution to overproduction. Third, use the Alcoa call to verify the bullishness Boeing ( BA) CEO Jim McNerney recently exhibited on "Mad Money" about the next 20 years. Klaus will give you an order book that can buttress that. Fourth, how quick is the natural gas change-over occurring? Aluminum is used in these turbines. Finally, I like this company for comment on beverage cans -- consumer spending -- and on trucks. The latter is huge, and one people don't talk about enough. Of course, people will look at the pathetic number or will catcall the company out for not doing an equity offering -- the bearish analysts -- or just talk about the gang that couldn't shoot straight. But, in reality, Alcoa has made so many right moves in a wrong industry that it's just not fair to criticize it. That's unless you expected, somehow, that this company would end up making makes the things that are packaged in aluminum, and not the aluminum itself. Action Alerts PLUS, which Cramer co-manages as a charitable trust, has a position in Ford.