|If the only factor preventing you from hiring this outstanding applicant is his lack of polished manners, then in a manner of speaking, you need to polish your hiring skills. When you find an applicant with questionable energy, persistence or interpersonal skills, then you would have a real basis for being concerned. But, table manners? They can be easily fixed.|
There is a cottage industry premised on providing up-and-coming professionals with training in manners, poise, and etiquette. If skills in these areas are truly important for success in your company, you could consider providing this individual, and presumably others in your company, with some training in this area.
However, it may also be helpful to step back and recognize that this individual has done well in his career to this point, in spite of his manners. Perhaps manners are less important for success in your industry than you may think. Either way, unless you have validated data that unequivocally prove that applicants who chew and talk with their mouths open tend to fail on the job, it would be impolite and impolitic to include table manners as one of your hiring criteria.