Steam is an effective means of sterilization of a bottling line. Taking advantage of the latent heat of vaporization, steam, because it is a gas, distributes heat everywhere in the line. As steam contacts the colder surfaces, it condenses and gives up its heat. When sufficient heat is delivered, sterilization is accomplished. In addition to the efficiency in delivering heat compared to hot water, steam can effectively deliver heat into nooks and crannies where it is difficult to get liquid water to go, ozonated or not. Most in-line filters also are rated for steam sterilization. (Check with the supplier.) As a result, the entire bottling line from filter to filler spout can be sterilized with steam, according to ARS/Pressure Washer Co., Calistoga, Calif.

When sterilizing a bottling line, especially with in-line filters, it is important to lower the steam generator's output pressure to not more than 25 psi. ARS/Pressure Washer recommends that a U.S. Federal Drug Administration- and NSP-approved steam hose rated at 100 psi and 300°F (149°C) be used with suitable fittings to attach one end to the steam generator and the other to the sanitary input of the filter housing or bottling line. All filler spouts should be open. It is also recommended by ARS/Pressure Washer that the steam output valve be opened part way until it is evident from dripping condensate that steam has passed through the filters. Once flow has been established, the valve can be opened all the way, which increases the flow keeps the pressure at a level never higher than 25 psi.

The inside surfaces of the bottling line will gradually heat up and liquid condensate will be pushed out of the filter spouts. When the inside surfaces of the bottling line are at 212°F (100°C), very little condensate and mostly steam will emerge from the spouts. To better ensure sterilization, continue the process continues for at least 15 min after achieving approximately 212°F (100°C). If the bottling line is to be used immediately, cool it down with clean tap water.