These are cold packs that are filled with a non toxic gel and frozen before shipped. One pack can keep yeast cool for up to 3 days in transit. In the summer, we suggest adding one extra ice pack for each extra day of travel, and at least one of these for every 2- 6 yeasts, especially in the hotter months. These packs are FROZEN when shipped, thus we advise you purchase no more than 1 Gel pack for every yeast ordered. The yeast may freeze if packed with too many gel packs.
We include one free gel ice pack with every order of liquid yeast. Purchase additional packs if needed. These ice packs can be reused dozens of times; simply re-freeze and they are ready for an ice chest or other application.