How do I pack jars of jam so they arrive unbroken?

Pack each jar so it cannot touch another jar or the box wall, seal each one in a leak-proof bag, and use a box inside a box. UPS asks for at least 2 inches of cushioning around items and, for fragile goods, an inner box surrounded by about 3 inches of cushioning inside an outer box at least 6 inches larger each way [1]. The Postal Service requires glass containers of liquid over 4 fluid ounces to be triple-packaged, with absorbent material, a sealed leakproof second container and orientation markings [2]. Before any of that, check that your state lets you ship cottage food at all; several do not [3][4]. This page gives the packing method, the carrier rules, transit heat and cold, and how to work out the cost.

Check that your state allows shipping

Shipping is a sales question before it is a packing one. Many cottage food laws limit sales to in-person delivery or to buyers in the state. Some examples, each as stated by the state source:

Every state's rule is on selling jam in your state, and online sales in general are on selling jam online. If your state allows shipping, the rest of this page applies.

Packing a jar to survive a parcel network

Parcels are dropped, stacked, tipped on their sides and shaken on conveyors. Glass survives that if it cannot move and cannot hit anything hard. This method follows UPS's published packing steps [1], with the Postal Service's liquid precautions [2] added because jam that escapes a broken jar behaves like a liquid.

1. Start with sealed, cooled, clean jars. Ship only jars that sealed properly and have been washed and labeled. Put a band back on each jar, snug, so the lid cannot be knocked loose.
2. Bag each jar. Seal each jar in its own zip-top or heat-sealed plastic bag. UPS's guidance for liquids is to seal containers and place them in plastic or spill-proof bags [1]. If one jar breaks, the bag keeps the jam off the others and off the box.
3. Add absorbent material inside the bag or around it, such as a folded paper towel or absorbent pad. The Postal Service's rule for liquids in glass asks for enough absorbent to take up all the liquid if the container breaks [2].
4. Wrap each jar. Use several layers of bubble wrap, with extra at the base and shoulders. UPS advises multiple layers on fragile items, especially at corners and edges [1].
5. Put the jars in an inner box with dividers. A corrugated divider insert (a grid of cardboard cells) keeps jars from touching. Fill any gaps so nothing moves when you shake the box.
6. Box the box. Place the inner box in an outer box at least 6 inches larger in length, width and depth, with about 3 inches of cushioning on every side, and fill any remaining space [1]. UPS recommends this two-box method for fragile goods [1].
7. Use real shipping tape on all seams. UPS says not to use masking, cellophane or duct tape, string, or paper over-wrap [1].
8. Mark the outer box. The Postal Service requires orientation arrows on the outside of liquid packages [2]. "This side up" arrows and "Fragile: glass" do no harm with any carrier.
9. Put a copy of the address inside, as UPS recommends, in case the outside label is torn off [1].
10. Shake test it. Close the box and shake it hard. If you hear or feel anything shift, open it and add cushioning.

Mailers for one or two jars

Molded pulp or foam shippers made for one, two or three jars are faster to pack than the two-box method and work well for small orders. Treat them as the inner package: bag the jars first, and if the shipper is not itself a sturdy corrugated box, put it in one. Test a shipper by sending a few jars to yourself or a friend before you use it for customers.

Carrier rules for glass

Whether jam counts as a "liquid" under Postal Service rules is not something the sources reviewed here answer. A jar of jam is a semisolid, but a broken one leaks. Packing to the liquid standard costs little and protects you; ask at your post office counter if you want a ruling for your product. Check, too, what the carrier pays for a broken glass shipment before you rely on its insurance.

Heat and cold in transit

Canned jam keeps best stored at 50 to 70°F [7], and a parcel truck in July is far hotter than that. Warm storage is a known cause of darkening and flavor loss in jam (see jam that darkened or lost flavor), and a hot truck is warm storage compressed into a few days.

What you can control:

• Ship early in the week, so parcels do not sit in a depot over a weekend.
• Avoid the slowest service in summer. A one or two day service spends less time in a hot truck.
• Watch the forecast for heat waves on the route, and hold orders for a few days if needed.
• Never ship freezer jam or refrigerated products by ordinary parcel. They are not shelf stable; see how long freezer jam keeps.
• Tell customers to unpack jars promptly and store them somewhere cool.

What it costs, and how to work it out

Carrier rates change, depend on distance, and are often charged on dimensional weight (the size of the box) rather than actual weight when the box is large and light. A double-boxed parcel is bigger than it looks, so dimensional pricing hits jam shipments hard. No standing figure would stay accurate, so price it this way:

1. Pack a real order of your most common size (for example, three half-pints) using the method above.
2. Weigh it and measure the outer box in inches.
3. Enter those figures in each carrier's online rate calculator for a near and a far destination in your allowed shipping area.
4. Add packing materials: outer box, inner box or shipper, dividers, bags, bubble wrap, absorbent, tape and labels. Price them from your supplier's case prices.
5. Add your packing time at the hourly rate you pay yourself.
6. Add an allowance for breakage, because some parcels will be lost or broken whatever you do. Track your own breakage rate and adjust.

Put the total into the cost per jar calculator as shipping per order. Compare the result for one jar and for three. Because the boxes, cushioning and packing time barely change, the cost per jar falls quickly as the order grows, which is why minimum orders and gift sets usually make more sense than single-jar mail orders.

Before the holiday rush

Holiday gift orders bring their own deadlines. Order cutoffs, holiday shipping planning and gift sets are on selling jam for the holidays. If a state rule or a buyer requires tamper-evident packaging for shipped jars, see tamper-evident seals.

References

1. UPS, How to Pack Your Shipments (packing steps for the United States), last modified January 12, 2026. https://ups.com/packagingsteps
2. U.S. Postal Service, Postal Bulletin 22516, Policies, Procedures, and Forms Updates: Publication 52 revisions for nonhazardous liquids (DMM 601.3.4), effective March 28, 2019. https://about.usps.com/postal-bulletin/2019/pb22516/html/updt_001.htm
3. Kentucky Cabinet for Health and Family Services, Food Safety Branch, Summary of Updates to Home-Based Processing, March 2021. https://chfs.ky.gov/agencies/dph/dphps/fsb/FSDocs/hbpupdates.pdf
4. New Jersey Department of Health, CFO-1 cottage food operator application instructions, not dated. https://www.nj.gov/health/forms/cfo-1instr.pdf
5. Illinois General Assembly, Public Act 103-0903 (amending 410 ILCS 625/4), effective January 1, 2025. https://ilga.gov/Legislation/publicacts/view/103-0903
6. UF/IFAS Extension, Q and A: Understanding Florida's Cottage Food Law (FS425), September 12, 2021, modified July 2, 2026. https://ask.ifas.ufl.edu/publication/FS425
7. National Center for Home Food Preservation, Storing Home Canned Jams and Jellies, October 2005. https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/storing-home-canned-jams-and-jellies/