Hi Ludger:

It depends on what you want to use Odoo for. Here are a few scenarios.

a. If you want to use just the Quotation/Sales Order/Invoicing and don't care about the Inventory tracking, you can set up one product called "Sealed Cheese" and enter the weight and price at the time of quotation/sale.

b. If you want to use the Inventory tracking too, you can still set up one Product as "Sealed Cheese" and use the "Lots/Serial Numbers" feature to keep a track of each pack of cheese individually. This assumes that you will always sell the whole pack.

c. If you can sell portions of each pack, you could create one Product for each brand/type of Cheese so that the Inventory can be tracked in gms. You can layer on the "Lots" feature to track which "pack" was sold.

There are more complicated scenarios that can be handled too.

EDIT:

Revising my answer, since I saw the "online store" part of the requirement after posting this. If you are trying to sell these products online, you will need to create a product for each sealed cheese pack individually since their dimensions and price are unique to each pack. This way your customers will be able to buy the specific pack that they are interested in.