By definition brandy is any fruit distillate, grapes just happen to be the most productive fruit for several reasons (high sugar content, produces on new growth, vine form, tartaric acid, etc.). However, any fruit fermented and distilled fits into the brandy category, but again most fruit is sold as-is for consumption and secondary, blemished, old etc fruit is mostly used for distillation. Again, good quality fruit can earn more income than a distilled product made from that fruit, mostly because alcohol taxes are so high.
Though non-grape brandies are produced around the world, there are some disadvantages. The first being that it is not as cost effective. It is not that fruit trees and bushes require more maintenance and pest control than grapes, it’s the sugar content is almost always lower than grapes, so you need more fruit which means more handling, equipment and waste, which are added costs. Apples made good distillate, but they can produce higher methanol levels, though safe, can still be a regulatory hassle. Plums are commonly used for brandy in Japan and Eastern Europe, but again the yield is the issue.
The one advantage is that well made fruit brandies can be FANTASTIC! The world has a lot of flavours that have yet to be explored through the distillation process and for people who like new experiences, fruit brandies are a fun way to taste the world.
Biochemistry of Apple Aroma: A Review. Food Technol Biotechnol. 2016
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5253989/
Pineapple Brandy: Process of producing brandy (Hawaii, 1936)
https://patents.google.com/patent/US2103449A
Recipe of the coconut fruit(s) flavored brandy
https://patents.google.com/patent/WO1984002719A1
Plum liquor, plum spirits, and manufacturing method thereof
https://patents.google.com/patent/JP2008221066A/en
Method for producing ume brandy
https://patents.google.com/patent/JP2004057036A/en
Preparation method for litchi fruit wine aquavit (2012)
https://patents.google.com/patent/CN101531959A/en
A Memoir on the Distillation of Persimons (Issac Bartram, Philadelphia. 1771)
https://babel.hathitrust.org/cgi/pt?id=hvd.32044107246217&view=1up&seq=2
Process for brewing persimmon wine
https://patents.google.com/patent/CN1159429C/en
Persimmon brandy wine and preparing method thereof (2008, China)
https://patents.google.com/patent/CN101215507B
Persimmon fruit cognac brewing method
https://patents.google.com/patent/CN104312882B/en