Select tender peas, shell them, then cook for five minutes in boiling water (if tied in a piece of butter-muslin or cheese-cloth, they are easy to lift out). Plunge into cold water, then pack them into jars, and fill up with water, to which one teaspoon sugar has been added to every pint, and the same of salt, although salt, having a tendency to harden, is better to be omitted, especially if peas are not very young. Adjust the rubbers and screw down lids loosely, or, in the case of spring-top jars, adjust the wire clamp but do not fasten down. Pack the jars in the boiler as directed in "General Rules For Canning Vegetables" and sterilise for one hour. Tighten the covers of jars and leave to cool in the boiler for 24 hours. The following day sterilise again for one hour, taking care to loosen the lids in order to let out steam, otherwise jars might crack. Repeat the process the third day, screw down the lids tightly or fasten down the clamps of spring-top jars, and put away in a dry, cool place.
If preferred peas may be sterilised for two hours the first day and repeated the second day, instead of one hour for three days.
The following excellent recipe is taken from a Buttetin on the "Bottling of Fruits and Vegetables," by Vincent and Georgiana Banks, published in England: -
Select good sound peas of even size; when they have just filled the pod is best, as it is a great waste to pick and preserve peas when they are not half-grown. Peas are at their best when fully grown, but not old. Only take the sweetest kinds for preserving, not the common field pea. After shelling put them into a pan of cold water, with a little salt, and a good sprig of mint. Place them on the fire and bring them to the boil, and boil for a few seconds only. Then take them off and cool in water - a running tap is best, but where a tap is not available, turn them into any vessel containing cold water. In the meantime pour enough boiling water to fill your bottles on to a little salt and sugar and a good sprig of mint, and stir it occasionally while cooling. Then fill up your bottles with the cooled peas, not too tight, as they expand slightly with boiling again; then fill up with the water already mixed, put on the cap, etc., and place in the saucepan and bring to the boil. Boil for If hours, when take out and fill up with boiling water if necessary; put on rubber ring, cap, etc., and fasten down tightly.
The above process will not make them retain their green colour. If you wish them to do this, add one heaped teaspoon of borax to each pint of water when you are mixing the salt, sugar, and mint for filling the bottles. Use plenty of mint in the above process.
[Author's Note. - My experience has been that here in South Africa peas cooked for less than four hours will not keep, probably due to climatic conditions. I would, therefore, advise a second boiling, according to the "Intermittent Process."]