I've been naturally priming my kegs with a boiled water (about a pint) and 1/3 cup of corn sugar mixture. I generally hit about 12 psi via this method. I leave the kegs inside at ambient temperatures (72F'ish) for about a week which seems to work well. However, after reaching it's 12 psi, I've been taking the kegs to my outdoor porch (around 32F) to crash cool. However, when I hook up my psi device, it shows the psi level to be around 5. I'm not expert on carbonation, but do you lose psi at colder temps?