I've used aluminium before. The pot sure is shiny after you make cheese ;-). The pot will pit after a lot of use. I noticed no difference in the flavour of the cheese, but I've heard that some people have a genetic ability to taste it. For making most cheese, it's not my first choice. For ricotta, though, aluminium is the best (or anything you want to simmer just under a boil). Different metals have different affinity for water and that affects the bubble size when it comes to a boil. For good ricotta where you are making a foam on top of the whey and the cheese is formed, floating in that foam, the aluminium can produce a better texture. It's not a huge amount, but it is noticeable to me. In Italy they usually use copper pots which give you that good texture and I've heard the dissolved copper adds some stability to the foam (somehow... I'm not too sure about the chemistry to be honest). It's toxic, I guess, but, hey... What's life without a few toxins?
I'm on IH heating now, so it's all stainless steel for me now. One other small thing is that the chromium in the stainless steel holds heat really well, so it's slower to heat up and slower to cool down. That's an advantage for normal cheeses. But... I still miss my aluminium pots for ricotta...
Edit: In that video, that pot is stainless steel. I agree that it looks like aluminium, but Gavin uses stainless... Though I think in the old, old, old days he used to use an enamel canning pot (green, I think...).
