A typical brine cure with TQ uses much higher concentrations...morton recommends a 20% (1 cup TQ per 4 cups water) solution by volume, not including spices.
The recipe I used for my CB if my math is correct (6 Tbls per 1/4 cup) is a concentration of 8.33%. It's alot less than is recommended. My reasoning behind this is I read a few threads here that methioned the high salt content, one stating that they would cut the recommended amount in half, even after a water soak. So, I opted for a longer curing time with a diluted solution.
My theory was partially correct in thinking this way. Though, I do not know at what point the concentration would become unsafe, or give unsatisfactory curing results.
Chris, if you went with 3 cups of water and 4 Tbls (instead of 6), then your concentration would have been 5.55%. This would have been a ratio of 0.66 to 1 or 66%---2/3 of the concentration of my recipe.
As I mentioned, not knowing at what point the concentration becomes unsafe is the question...and you won't find out unless you push the envelope, cut one open and find that it did not cure completely. Then, there may be a slight risk of microbial problems during the cure/smoking...don't know for sure on that one though...I know that I personally don't want to experience that.
I just cringe at the thought of cutting open a piece of cured meat to find that it didn't fully cure to the core.
A reduced salt content cure would be a better choice than pushing the margins of safety. I don't have those types readily available, so I'm playing the TQ game.
Eric