Selling online and shipping glass
Updated
The state line
Shipping across a state line is the thing most likely to put you outside your exemption, and it does so regardless of how the product is made. This is worth settling before building a shop rather than after the first order arrives from somewhere else.
Cottage food exemptions are state law, and most of them contemplate sale within the state. Shipping to another state is not obviously covered by either state's exemption, and that is a question for your state department of agriculture rather than for a marketplace's help page.
The weight
Jam is dense and glass is heavy, and the combination makes shipping a larger proportion of the price than almost any other craft product.
A jam is sold by weight and glass adds its own. A case of twelve half-pints is heavier than new sellers expect, and the shipping cost on a single jar is often a large fraction of its retail price. Selling in twos and threes is the usual answer, which is a packaging decision as much as a pricing one.
Packing it to survive
Breakage is movement rather than impact, which means the packing problem is about immobilizing jars rather than cushioning them.
- Jars that cannot touch each other or the wall of the box.
- Enough fill that nothing shifts, because movement is what breaks glass.
- A box rated for the weight, not the size.
Case packing is covered properly on shipping it by the case.
Temperature in transit
Weeping has storage temperature and fluctuation among its two published causes, and a parcel spends days in neither. That is a real risk on a long summer route and it is on it is weeping liquid in the jar.