Omega yeast packages will sometimes swell slightly, or moderately during shipping or later while properly stored. This is not an indication of deterioration if the package is less than 6 months old and has been properly handled. This is result of trace amounts of nutrients, still available at the time packaging, causing small amount of culture activity and CO2 production. Some strains are more prone to this than others.
All liquid yeasts will be shipped with a complimentary cold pack, however we cannot guarantee cold packs will stay frozen. During the warmer months, we recommend ordering a dry yeast instead.