Important: Safety Warning
This page describes home-canning methods from before the causes of botulism were understood. Canning low-acid foods without a pressure canner, as described here, can allow the growth of Clostridium botulinum, whose toxin is among the deadliest known. Follow current USDA home-canning guidelines instead.
This information has been left in for historical purposes but should not be acted upon.
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Preservation of Fruit and Vegetables by Canning, Etc
IN cities and large towns fresh fruit may be obtained throughout the year and the necessity for "putting up" a large quantity of fruits no longer exists. But if one is distant from markets and, especially, if one has more of any variety of fruit or vegetable than can be made use of while fresh, the surplus should be made available for future use.
Micro-organisms exist everywhere, and under favorable conditions for growth, as when moisture, warmth and proper food are present, they multiply. These organisms grow rapidly in food stuffs containing nitrogen, as meat, fish, eggs, milk and beans, but they do not find so suitable matter for growth in fruits containing much acid and little nitrogen. Lemons, cranberries and rhubarb contain so much acid that they are rarely attacked by micro-organisms. In preserving vegetables and fruit the micro-organisms on the article or the utensils with which the articles must come in contact during the process of preservation must be destroyed, then the product must be sealed to exclude germs from without. But there are many kinds of micro-organisms; some produce spores which (like the dried seeds of plants) may retain their vitality for a long time, even under conditions that destroy the parent germ. Thus while the parent organism might be destroyed if the food product were exposed ten or fifteen minutes to the temperature of boiling water, the spores would require for their destruction exposure to heat at 212 deg F. for an hour or more. We have no means of knowing just what micro-organisms may be present in the articles we wish to preserve, but it has been found that, usually, the germs that thrive in fruits and fruit juices can be destroyed by cooking ten or fifteen minutes at a temperature of 212 deg F. To sterilize the utensils put the spoons, jars, covers and such other articles as are to be used over the fire in cold water, let heat gradually to the boiling point, and then boil ten or fifteen minutes. Take the jars from the water, one at a time, and fill at once with the hot material. It is well to let the can set on a cloth, saturated with boiling water, while it is being filled; fill to overflow, leaving no space for germ laden air. Adjust the rubber, take the cover from the boiling water, set in place and close securely. The covers of Mason jars need to be screwed down more tightly when the cans are cold. Never use a rubber twice; purchase a new supply each season. Jars holding a pint or a half pint are the best size for a family of two.
PREPARATION OF FRUIT FOR CANNING Articles preserved by sterilization, or the destruction of all germ life, are said to be canned. The addition of sugar, as in the canning of fruit, has nothing to do with the success of the process. The fruit will keep just as well, if no sugar be used. If the fruit is to be served with bread and butter, sugar may be added to make it palatable. If fruit juice be put up for use in frozen desserts, omit the sugar. Fruit for canning may be cooked in an open kettle and transferred to the can, or it may be cooked in the jar in which it is to be stored. Prepare the syrup, add the fruit, peeled and stoned as necessary, then cook the required time and seal as directed. Rhubarb, cranberries and green gooseberries, on account of the large quantity of acid in their composition, may be successfully canned without sterilization by cooking. It were safer, perhaps, to sterilize the jars and covers, though, if bacteria were present, they migh not attack these foods. CRANBERRIES CANNED FOR SUMMER USE Heat fruit jars gradually, then rinse jars and covers in boiling water. Put as many cranberries as possible into each jar, then pour in cold water to fill the jars to overflow; adjust the rubbers and covers and set the jars aside in a cool place. Green gooseberries may be canned in the same way. CANNED RHUBARB Sterilize jars and covers. Cut the peeled stalks of rhubarb of a length to come nearly to the top of the jar and fill to overflow with fresh-drawn, cold water; adjust rubbers and covers and store in a cool, dark place. GRAPE JUICE Wash the grapes and pick them from the stems. Set them in a preserving kettle over the fire, crush with a pestle and let them slowly heat to the boiling point. Let cook until the skins are tender (about fifteen minutes), then strain through two folds of cheese cloth, pressing out all the juice possible. Heat the juice to the boiling point and turn into sterilized jars, filling them to overflow; put on rubbers and sterilized covers; or store in sterile bottles with sterile corks and sealing wax. For ices it is preferable to put up fruit juices without sugar. For other use sugar may be added. Use half a cup of sugar to a quart of juice.
BERRY AND CURRANT JUICES The juice of berries and currants may be canned in the same manner as grape juice. Such juice may be made into jelly at any time. Raspberry and strawberry juice are particularly good for sherbets, punches and the like, and for these uses they should be put up without sugar. When using sugar take a cup for each quart of juice, except currant juice. On account of the acidity of currants take a pint of sugar for each quart of juice.
This chapter is a snapshot of what a careful cook knew about food preservation before the microbiology of canning was settled, and its central claims have since been disproven. It is worth reading as a document; the methods themselves have been superseded and several of them are dangerous.
- The author names the problem and then dismisses itThe text correctly states that spores may survive fifteen minutes at 212°F and need an hour or more, then concludes that ten to fifteen minutes is "usually" enough. Clostridium botulinum spores are not reliably killed at boiling-water temperature at all; they require 240–250°F, which only a pressure canner reaches. The gap between the observation and the conclusion is exactly where botulism lives.
- Cold-water raw packs are the worst of itThe cranberry, gooseberry and rhubarb methods put raw fruit and unboiled cold water into a jar, seal it, and set it aside in a cool place with no heat processing of the contents at all. No seal is formed by this method either — a screwed-down lid on cold contents does not vacuum-seal — so the jars are simply covered containers of wet fruit stored at cellar temperature.
- Rhubarb and cranberries are acid, but not a licenceThe reasoning that high acid protects against spoilage is broadly right and is the basis of modern boiling-water canning, but the author hedges with "it were safer, perhaps" and "might not attack these foods." Current practice measures acidity rather than guessing at it, and pH 4.6 is the line that decides between boiling-water and pressure processing.
- No processing after fillingNothing here is processed in the jar after sealing. Hot-fill-and-seal was standard practice for decades and is no longer accepted for home canning, because the headspace, the jar rim and the underside of the lid are not held at temperature long enough.
- The vegetable questionThe title promises vegetables, and the opening paragraph correctly identifies meat, fish, eggs, milk and beans as the high-nitrogen foods where organisms thrive. Low-acid vegetables cannot be safely canned by any method described on this page.
- Rubbers and jar hardwareThe advice to buy new rubber rings every season was sound and its modern equivalent still holds: flat lids are single-use, and bands and jars are reused only if undamaged. Rubber-ring jars with glass or zinc lids are no longer recommended for canning of any kind.
- Grape and berry juicesBoiling the juice, filling sterilised bottles and sealing with corks and wax will produce something drinkable more often than not, since fruit juice is acid, but the corked-and-waxed closure gives no reliable seal and no way to confirm one. A current tested recipe should be used for fruit juice as well.
- If you want the fruitFor any of this — juice, rhubarb, cranberries, jam — use a current USDA or National Center for Home Food Preservation recipe with stated jar sizes, headspace and processing times. Freezing the fruit or juice sidesteps the question entirely.
Cooking for Two belongs to the era when domestic science was being taught as a science, and this chapter shows the ambition and the limits of that project. The germ theory of food spoilage was well established by the early twentieth century, and the author explains spores, sterilisation and the nitrogen content of foods with real accuracy; what was missing was the recognition that boiling-water processing cannot reach the temperature that kills the spores she describes. That gap was closed over the following decades, as canning-related botulism outbreaks — including a widely publicised cluster traced to commercially canned olives around 1919–20 — pushed both industry and the U.S. Department of Agriculture toward pressure processing and published, tested times. The opening remark that city dwellers no longer need to put up fruit is itself a period detail: refrigerated rail transport and year-round urban markets were already making home preservation a rural and thrifty practice rather than a universal one, and the note that pint and half-pint jars suit a household of two is the whole premise of the book in a single line.