I've read that a combination of the one-two punch of Potassium Sorbate (to prevent the yeast from reproducing) and Potassium metabisulfite (to kill existing cells) along with cold crashing to slow fermentation while the chemicals work their magic will destroy the live yeast in a beer. I...
@hockeybrewer - I was where you are about 2 months ago. My very first batch I had a terrible time with temperature control. It was very frustrating trying to maintain an even 153 degrees although in the end, the beer turned out very good. Do yourself a favor and order a roll of Reflectix (?)...