Jam Economics 101

I've been attempting to make some jam the last couple of weeks. Here is the breakdown on what it costs to make jam (or in my case, syrup, or candied fruit).

Blueberries:
Ingredient Cost: $25 (for 12 pounds of berries)
Jar Cost: $15
Labor: 3.5 hours
Yield: 28 jars
Potential Market Value: $112
Net profit: $72
Profit Per Hour Labor: $20.50

Peaches:
Ingredient Cost: $10 (for 25 pounds of peaches)
Jar Cost: $15
Labor: ~6 hours
Yield: 28 jars
Potential Market Value: $112
Net profit: $87
Profit Per Hour Labor: $14.50