When canning tomato juice, many gardeners prefer to use a variety of red beefsteak tomato because they are both acidic and juicy. The skins and seeds need to be removed before bottling, and a food mill or sieve can help with this task. Cooks can generally prepare their jars and lids at the same time they are cooking the tomatoes, and this can help save time when performing home canning. Boiling tomato juice is very hot and may cause burns; it may also expand and cause canning jars to burst if they are over-filled.
Some good varieties to consider when canning tomato juice include Early Girl, Brandywine, and Better Boy. These varieties have a somewhat sweet flavor and a thinner flesh than others. More than one variety of tomato may be used, but cooks should avoid using cherry or plum tomatoes to make juice because these varieties are normally too meaty.
The skins and seeds of the tomato need to be removed because they can make the finished product difficult to drink. Many people use a sieve or food mill, which somewhat resembles a strainer. This is an effective method, but can be time-consuming because the tomatoes must be manually processed. An alternative method might be to use a juicer, which causes the seeds and skins to become liquefied, which eliminates the need to run them through a manual sieve.
When canning tomato juice, both the tomatoes and the canning jars need to be boiled to kill bacteria. This can be done simultaneously, which helps to ensure the jars are ready for open kettle canning as soon as the tomatoes have processed. The jars should be boiled separately from the lids and rings, and both should be washed in hot soapy water and rinsed well before being sterilized.
It is very important to fill canning jars from between 1/4 and 1/2 inch (0.64 to 1.8 cm) of the top rim when canning tomato juice. This can allow the finished product to expand without causing the lids to pop or jars to crack. It can be a good idea to use a funnel to help fill the jars, and the liquid should be poured very slowly to keep it from splattering. Once the juice has been processed by open kettle canning, a jar lifter can be used to remove them from the kettle to prevent burns to the hands and arms.