Now that first Lady Rosalynn Carter is serving typical American foods at White House state dinners and nouvelle cuisine is sweeping the French country side, there's renewed interest in grandma's cockery. A timely tome on the subject is Grace Firth's "Stillroom Cookery" (EPM Publications of McLean, $9.95.), the art of preserving foods naturally with recipes for everything from beef corn soup to homemade yeast.

"Stillroom Cookery" is the first general cookbook to use both standard and metric measurements. And it's as old fashioned as a hundred-leaf rose in my grandmother's flower garden.

Firth learned to garden, preserve and cook in the old ways from her grandparents with whom she lived as a child, she writes. And she tells all in a delightful way.

I'll admit I may be prejudiced. Althougn I never met Grace Firth, I used to watch her on TV ("Panorama"). Her food demonstrations were deliciously different. My favourite was the day she made homebrew. (I remember when my dad made homebrew in our basement during Prohibition, much to my mother's consternation and disapproval.)

The author gives complete directions for making homebrew as well as all kinds of beer, wines and spirited liquor. She warns would-be winemakers fill out tax form No. 1541.

The beverage chapter in "Stillroom Cookery" is unique, but the most useful to modern cooks is the remainder of the 200-plus page. They contain everything from raised dough and yeasty treats to vinaigres bons and saucy secrets. There's even a recipe for flowers vinegar and a list of common flowers used in stillroom cookery - plus a warning about poisonous ones.

If you are interested in preserving your homegrown or store-bought food, the book covers techniques from broiling and canning to drying, smoking, pickling and making sweet spreads. There's even a garden planting chart for a family of five in the appendix, and a guide to basic food equipment in both metric and standard measurements.

The chapter on cured meats tells more than you may want to know about preserving beef, pork, lamb and game. In stillroom days the art of home-curing meats was noteworthy , writes Firth, who tells how to smoke, sugar-cure and corn beef. Her recipe for Broiled Corned Beef with Horseradish is the best I've tried.

One of the most ambitious cookbooks to date, "Stillroom Cookery" will appeal to young cooks who are putting their faith in the old ways as well as to old hands in the kitchen who remember grandmother's way with food.

Note: Elinor Lee is a retired Food Editor of The Washington Post.