I have been using a Gaggia Classic for about 2 years and I am fairly proficient at obtaining a good latte. I have a problem that occurs occasionally with my milk steaming. The milk becomes a mess of large bubbles with almost no froth at all. This has occured before and I seem to go through a period of a week or so of it, before it comes back to normal. I have tried different milk, de-scaling, etc. I use the turbo frother, and normally obtain quite good results.