Deanna is the owner of a recently closed gas station. Joon, a neighbouring filling station owner, agreed to buy the gasoline remaining in Deanna's tanks. Deanna tested the gasoline for the presence of water, which would destroy the gasoline, and found it to be "clean." Deanna then called Joon informing him of the test results and quoted him a price. Joon reaffirmed his agreement to buy and arranged pickup of the gas two days later. During the intervening 24-hour period a large amount of snow fell and then melted. With the excess amount left on the ground, water drained into the tank and ruined the gas. Upon hearing this, Joon refused to buy, but Deanna pointed out that the gas was already Joon's and insisted on payment.

Advise Joon of his rights (if any). Refer to rule of transfer of title in this case. Define and explain any legal concept you use.