Q. How is self-rising flour different than regular flour? Can I make it myself? And how long will it last?
-- Tracy Byle, Penticton, British Columbia
A. Self-rising flour is white wheat flour to which a leavener -- baking powder -- and salt have been added. It is often called for in recipes for tender baked goods, such as muffins, quick breads and biscuits.
Where it isn't available, you can either adapt your recipes and add the necessary leavener, or you can make and store your own self-rising flour by combining 1 1/2 teaspoons of baking powder and 1/2 teaspoon salt per cup of all-purpose flour.
In most cases, you should not substitute self-rising flour in a recipe that calls for all-purpose flour; if you choose to, when making a quick bread, for example, you must remember to omit the additional salt and baking powder that the recipe calls for, or you'll have too much leavening.
Whether you make your own or buy a commercial brand, the shelf-life of self-rising flour is somewhat less than that of regular flour, since the baking powder absorbs moisture and loses its effectiveness over time. Stored in an airtight container, however, it should keep for several months.
Jades and other gems
Q. How should I care for jade jewelry?
-- Becky Dela Cruz, Tacoma, Wash.
A. Jade -- a colored gemstone that has been prized for thousands of years for its elegance and soft, opaque luster -- is quite durable, but, like all gemstones, should be treated with care.
True jade is actually one of two types of stones: jadeite or nephrite. Jadeite, the rarer of the two, is strong (it has a hardness rating of 7) and comes in many colors including green, red, yellow, orange, blue and even brown and black. It is also known as Imperial jade. Nephrite is more commonly available and comes in a range of green tones.
Jade is usually carved to enhance its natural beauty. It is often used for pendants, statues and the like. Many jade pieces, particularly newer ones, are coated with a waxy finish to add shine, and this finish can be damaged if cleaned incorrectly.
If possible, check with the jeweler who sold the piece for specific care advice. If such expert information is not available, be sure to take a gentle approach: Avoid boiling or high heat cleaning. Instead, try a brief soak in a sudsy ammonia-and-water solution, then brush carefully around the setting with a soft eyebrow brush. Rinse well and allow to dry.
Follow common-sense care advice for all fine jewelry and precious gemstones. Wipe jewelry with a soft, damp cloth when you remove it, and always store it clean. Keep each piece in a soft pouch or specially designed jewelry box when you're not wearing it. Never store multiple items together where they can bump into each other.
Remove rings when doing any rough work, when washing dishes or using harsh household cleansers, or when swimming; salt water, chemicals and chlorine can be damaging to the finish of the stones.
If you wear your jewelry a lot, it's wise to have a professional jeweler check it once a year or so. He or she will clean it thoroughly and safely and check the security of its setting.
Pure and clean
Q. What exactly is distilled water, and what are its household uses?
-- Karen Levine, Newton, Mass.
A. Distilled water has been purified in a process by which it is heated to boiling, captured as steam, then condensed back into water. When the water evaporates, the steam rises and leaves behind minerals, pesticides and other contaminates. When that steam is condensed, the water that is left is pure and clean.
Many people prefer to use distilled water for drinking and cooking, particularly those who live in areas where the tap water is "hard" -- meaning it has a high mineral content -- or otherwise seems to have a high level of contamination.
Outside the kitchen, distilled water has a number of household uses. It's a good idea to use it in place of regular tap water anywhere that a build-up of minerals or chemicals could pose a problem -- such as in cleaning contact lenses. It's also good for watering plants, using in room humidifiers and in steam-irons -- since mineral deposits can clog steam vents over time.
If you decide to use distilled water, you can either buy it in bottles at your local grocery store or process your own with a home distiller -- available at some hardware and housewares stores. Countertop water distillers range in price from just over $100 to several hundred dollars -- though if you plan to use a great deal of the processed water, buying your own unit can save money in the long run.
Questions should be addressed to Martha Stewart, care of New York Times Syndication Sales Corp., 122 E. 42nd St., New York, N.Y. 10168.