Campden and yeast

So - on my Octoberfest, I discovered a sharp astringency to it using my local tap water. A poster suggested crushing a Campden tablet to the boil water to remove chloramine(sp) because this does not boil out. I did this, and something odd happened that has not happened on a hundred or more prior batches - my yeast seemed to drop off too early. OG was 1.050 and FG was 1.018. Fermentation was slow to start, but blew good for several days. I added yeast nutrient to this batch to try to counter the Campden affects.

My question is this - is 1 tablet for 5 gallons enough to cause this?

It's possible. 1 tablet per 20 gallons is the usual amount for treating chlorine and chloramines. The boil should have driven off most of the excess, I would think, but any that remained would make reproduction much more difficult for your yeast. If they never reached a sufficiently high population, it's possible they could have flocced out early, I suppose. Good luck with this brew, but next time, make sure to use it in the proper amount.

ok I have done a ton of reading and things get mixed up in my brain so please forgive me...

but when making wine don't you add campden before adding it to the primary and pitching yeast? And then add it again during rackings? I don't think the campden bothers the yeast does it? I know if you want to back sweeten your wine you can add sugar and then .... Something... To sterilize the yeast (cant think of name)

you add 1 campden tablet per gallon (for wine) ... Unless campden has a totally different effect on beer and beer yeast... As this is the first time I've seen it mentioned on here...

and I could be totally wrong! :/

You add 1 campden per gallon of must to initially kill/ stun wild yeast and bacteria. After 24 hours you add wine yeast which is rumored to have a tolerance to sulfites (campden). You wait because the sulfites will precipitate out. After fermentation is complete you add about 1/4 tsp sulfites( equall to about 5 or 6 campdens i think) every 3 to 4 months to keep it from spoiling. You can also add sorbate which stops the yeast from procreating.

I usually add 1/4 to 1/8 tablet to my water before brewing. I usually mix it in first with the other water salts and let it sit for a bit while I prep everything else. I've never used 1 hole tablet but I wouldn't think it would do anything after being boiled. Its also a lot less then what you add to wine initially. ??????