The only risk with making your own pear juice is the high pH of the juice, and the fact so2 doesn't work so well due to binding by acetaldehyde found in pear juice - probably why straight pear juice isn't sold so often. I have lots of pears I will be juicing at Bathurst, I have a nashi covered in pears I probably won't even use. The juice is nice but not a lot of flavour, the best thing is the unfermented sugars give it a bit of body.