For a smaller turkey you may make less brine; however, be careful to do so with the original proportions of ingredient still intact. Too much salt will leave you with an incredibly salty turkey. To estimate your brining time plan 45-60 minutes per pound of the turkey.
Brining should only be used on turkeys that have not previously been soaked in a salt water solution. Fresh, unfrozen turkeys are prime candidates for brining. If you plan to use a previously frozen turkey, check the label first to see if it was soaked in a salt water solution. If unsure, call the phone number listed on your turkey’s packaging to speak to a company representative.