How much chloramine to be noticeable?

[goodsuds]

My tap water is treated with chloramine. To get around it I use campden tablets to treat my water when I do partial mashes or use distilled water when doing all extract. Before I did this my beers would all develop a plastic taste that was unmistakable.

My question is, if I used my (non-campden treated) tap water (~2 cups) to rehydrate dry yeast or make priming solution for a 5-6 gallon batch, would either result in detectable off flavors? I understand at a basic level how chlorophenols are produced during fermentation, I just don't know enough to understand at what volume they become detectable, or how to measure it other than by volume of water.

Yes, I could just use spring water, and I typically do, but sometimes it slips my mind to buy some on brew day, or I had to use all of my campden treated sparge water (which I usually try to save some for rehydrating) and I end up having to rehydrate my yeast in distilled water, which I understand to be less than ideal.

Thanks in advance.

 

[Captain Damage]

I would use "clean," i.e., non-chlorinated water wherever you can. Whether the amount of chloramine in your hydrating water is enough to be noticeable, I'd say probably not. But very small amounts of chlorine/chloramine can get greatly magnified by fermentation. Also, keep in mind that the purpose of chlorine/chloramine is to kill microorganisms, of which yeast is one.

Can't you just hold back an extra pint of treated water and keep it in your fridge for hydrating?