To help the chocolate to crystallize during the tempering process, our machines use a method called seeding. The "seed chocolate" is chocolate that has already been tempered and successfully formed the desired crystals in it. When seed chocolate is added to a batch of melted chocolate during the tempering process these crystals of tempered chocolate act like magnets, attracting the other loose crystals of fatty acids to begin the crystallization process. Seeding will ensure your chocolate tempers faster and more reliably.
Seed chocolate can come take various forms, chunks, pieces, pistoles, wafers, ground or grated chocolate all work fine.
Seed chocolate is not hard to find, almost any solid chocolate bar you can buy commercially is already tempered. Or simply reserve a small portion of the solid chocolate you are melting (to temper) and set it aside to use as your seed.
If you are making your own "bean-to-bar" or "raw chocolate", and you do not want to introduce any other chocolate to your recipe, you may need to hand temper a batch to use as your first seed - and then just keep a small amount from each batch going forward to use as seed for your next batch!