I apologize for the delay in this reply, but it looks like my attempt to neatly format this message broke my past posting attempts. First and foremost, the water tank on that machine is the only plastic component exposed to the water--everything else, from the pump to the brew head or steam arm, are brass, nickel, stainless, copper, or rubber (with the exception of some small seals in the steam valve assembly, which are teflon, and the silicone hoses leading to the pump and from the OPV). As this part is not actively heated, it will pose no health risk or put any of the water at risk of contamination. I'm not familiar with any other tank options that are available. The Silvia can be a tough machine to master brewing with, but here are some suggestions: 1. Make certain that the machine is fully warmed up before brewing. This includes rinsing a small amount of water through the portafilter to pre-warm its brass body and to help pre-warm the cup. 2. Shortly before pulling a shot, run a small amount of water through the group head, making sure the portafilter is removed. This will help to clear out any super-heated water that might be in the brew head or sitting atop the boiler. 3. After steaming, always make sure to flush at least one ounce of water through the steam arm. While the amount doesn't really matter too much, what's important is that water is able to come through smoothly--Since the steam valve pulls from the top of the boiler, a consistent flow means that the boiler is properly filled. Finally, do your best to stick to the golden rule (2 to 2.5oz over 20 to 25 seconds) and feel free to experiment. What works for one person may not work for someone else, even if they have the same equipment. Don't hesitate to tinker and adjust the settings on your grinder or adjust your tamping technique to help achieve these ends on a consistent basis. More often than not, inconsistent shots with the Silvia can be pointed back to small variations in one or more of these factors.