The key is that not all tap water is the same. The extremes being places with severe tap water contamination (Detroit) but even acknowledging that as highly unusual, there is still the potential for local treatment systems seasonal changes in the water treatment processes they use. Here in NW Arkansas our lake water, while safe to drink, gets extra doses of Chlorine when the lake water "Turns over" (Don't ask me to splain that) when that happens our tap water has a distinct Chlorine smell and that's not something I want to add to my wine in any quantity.
One additional point about tap water. When I make my sanitizing solution with Star San lately I've noticed that it has turned cloudy within hours - That is one condition that the manufacturer states is an indication that your solution should be discarded. So for my last batch of Star San I used Purified water and Surprise it has stayed crystal clear now for over a week. Point is that sometimes there are things in our tap water that still meet standards but may not be great for what we are doing. So I have decided to be sure that the last solution that touches my equipment before it is used is a no-rinse sanitizer AND I will be using at least purified water instead of tap water for all other wine making activities like my Simple Syrups or water additions to my initial wine batch solutions.
I use Star San and I consider their directions to mean not to use something sanitized with Star San for at least a minute after sanitizing. I know that the film of water on things sticks around for at least that long so unless I immediately rinse with tap water or bring the treated item into contact with my wine must before 1 minute, the sanitizing action should be effective.
First, you are confusing Detroit and Flint. Flint's water problem is not bacteriologic; it occurred when the city switched their water source
from Detroit to the Flint River, and then failed to treat the water with corrosion inhibitors, causing lead to leach from pipes.
The cloudiness of Star San is related to the
minerality of the water used, not to bacterial contamination, chlorine, or other additives. Using RO or distilled water it will keep it clear. So long as the pH is below 3.0 it is still OK to use.
I agree with your interpretation of correct Star San use. But let's be clear, without rinsing Star San you are adding trace amounts of dodecylbenzene sulfonic acid,
a major component of laundry detergent, to your wine. And to put this in perspective,
the dodecylbenzene sulfonic acid in Star San is 300ppm and chlorine in tap water is maximum 4ppm, usually under 0.5ppm. I see no reason to be concerned about the chlorine in the rinse water left on the racking cane, when the concentration the dodecylbenzene sulfonic acid in the Star San left on the racking cane is on the order of 1000 times higher.
I think that humans have a hard time accurately assessing and quantifying risk. My point in these posts is that rinse or not, it probably doesn't matter that much; the vast majority of risk surrounding sanitizers is probably tied to inadequate contact time and improper use.
