Food Preservation

Evidence-based guides to freezing, canning, drying, and storing food without risky folklore.

Preserving food saves money only when the result is safe, used, and replaces a later purchase. These guides separate tested methods from viral shortcuts.

25 practical guides

Choose the safe form first

The same food can require a different method.

Cutting, puréeing, acidifying, or thickening changes how heat moves through a jar. Match the exact food form to a complete tested process.

Safe preservation method for foods covered by Plain & Frugal canning guides
Food and form	Safe method	What to know	Add only after opening
Unsweetened applesauce	Water-bath hot pack	Sugar is optional; process pints 15 minutes or quarts 20 minutes at 0–1,000 feet, longer above that.	Sweetener or spices, if wanted
Thickened apple pie filling	Use cook-type Clear Jel	Cornstarch, flour, tapioca, instant Clear Jel, and pectin are not substitutes in the tested recipe.	Alternative starch only after opening plain canned apples
Broth-based homemade soup	Pressure-can only	Fill jars halfway with solids; process pints 60 minutes or quarts 75 minutes.	Pasta, rice, flour, milk, cream, and thickeners
Pumpkin or winter squash purée	Freeze; do not home-can	No tested water-bath or pressure-canning process exists for the purée.	Nothing needed; freeze the finished purée
Pumpkin or winter squash, 1-inch cubes	Pressure-can only	Hot-pack cubes in liquid; process pints 55 minutes or quarts 90 minutes.	Purée the drained cubes after opening
Plain green beans	Pressure-can only	Process pints 20 minutes or quarts 25 minutes at the correct pressure.	Butter, bacon, dairy, or thickeners
Whole, crushed, or juiced tomatoes	Acidify every jar	Use bottled lemon juice or citric acid plus the complete tested heat process.	No required finish; acid goes in before processing
Apple butter	Use a complete tested recipe	Refrigerate or freeze an improvised recipe; a sealed lid alone is not proof of safety.	Only ingredients allowed by the tested recipe

Review the safe old-fashioned preservation methods

Sugar is recipe-specific

When can you safely leave the sugar out?

Sugar may be optional for flavor in one tested process and essential to another recipe's structure. Check the product before changing it.

How sugar functions in common apple preservation methods
Product	Sugar rule	Safe next step
Applesauce	Optional for flavor	Use the tested hot-pack process and altitude-adjusted time with or without sugar.
Plain apple slices	Optional in the packing liquid	The USDA method permits hot water or tested syrup strengths; use the full fruit-canning process.
Apple pie filling	Follow the tested formula	Do not change the sugar, bottled lemon juice, or cook-type Clear Jel proportions.
Jam or jelly	Recipe-dependent	Use a tested reduced-sugar or no-sugar pectin recipe; do not alter a regular-pectin formula.

Follow the complete unsweetened applesauce method

Canning thickener checkpoint

Clear Jel products are not interchangeable.

The tested apple pie filling uses cook-type Clear Jel. If you do not have it, freeze the filling or can plain apples with a separate tested recipe and thicken after opening.

Which thickeners can be used in tested canned apple pie filling
Product	Canning verdict	Appropriate use
Cook-type Clear Jel	Use only as specified	The tested NCHFP canned apple pie filling
Instant Clear Jel	Do not substitute	Some freezer or fresh fillings; not the tested canned filling
Cornstarch, flour, or tapioca	Do not substitute	Add after opening plain canned apples, or use in a freezer recipe
Sure-Jell or other pectin	Do not substitute	Use only in the jam or jelly recipe that specifies it

Read the complete apple pie filling safety guide

Canning safety checkpoint

Acidify every jar of tomatoes.

These USDA-based amounts apply to whole, crushed, and juiced tomatoes. They do not replace the complete tested recipe or its heat-processing step.

Required acid per jar for whole, crushed, or juiced tomatoes
Jar size	Bottled lemon juice	Citric acid	5%-acidity vinegar
Pint	1 tablespoon	¼ teaspoon	2 tablespoons
Quart	2 tablespoons	½ teaspoon	4 tablespoons

Read why the acid is still required with pressure options

Quick preservation answers

Can you skip blanching?

Sometimes—but not for every vegetable. Use this comparison to choose the right guide before you start cutting.

Freezing preparation for produce covered by Plain & Frugal guides
Produce	Direct answer	What to know
Mushrooms	Steam or sauté first	Steam whole 5 min, buttons or quarters 3½ min, or slices 3 min; leave ½ inch headspace.
Broccoli	Water 3 min; steam 5 min	Use florets no more than 1½ inches across; cool, drain, and pack with no headspace.
Spinach and tender greens	Blanch 2 minutes	Collards need 3 minutes; cool for the corresponding time and drain thoroughly.
Raw eggs	Remove shells; mix and freeze	Never freeze intentionally in the shell; label salt or sugar additions.
Pumpkin purée	Cook, cool, and freeze	Leave ½ inch of headspace; do not home-can purée.
Apple slices	No cooking required	Use a measured ascorbic-acid treatment, then tray-freeze for loose slices.
Carrots	Blanch 2 or 5 minutes	Pieces need 2 minutes; small whole carrots need 5 minutes.
New potatoes	Blanch 3–5 minutes	The NCHFP method is specifically for smooth new potatoes; time depends on size.
Cabbage	Blanch 1½ minutes	Use medium-to-coarse shreds, thin wedges, or separated leaves.
Eggplant	Blanch 4 minutes	Use ⅓-inch slices and add ½ cup lemon juice per gallon of water.
Okra	Blanch 3–4 minutes	Sort by pod size; small pods need 3 minutes and large pods 4.
Bell peppers	No blanching needed	Cut and tray-freeze raw; best for cooked dishes.
Tomatoes	No blanching needed	Freeze raw for sauces, soups, and other cooked uses.
Green beans	Blanch 3 minutes	The tested method better protects color, flavor, and texture.
Corn on the cob	Blanch 7–11 minutes	Time depends on ear size; cool for twice the blanching time.
Zucchini slices	Blanch 3 minutes	Use steam blanching for grated zucchini.
Peaches	Sugar is optional	Use an anti-darkening treatment; sugar affects quality, not safety.

Check more produce in the free preservation toolkit

Plain & Frugal research library

Start with the question you need answered.

Every guide opens with the direct answer and names the evidence behind safety or savings claims.

Fresh mushrooms beside a steamer, sauté pan, cooling setup, and freezer-safe containers

Food Preservation · 8 min read

Can You Freeze Mushrooms Raw?

Raw mushrooms will freeze, but steaming or sautéing first gives more dependable quality. See exact steam times, anti-darkening treatment, and packing steps.