Here is some information from Fleischmann's Yeast website. I usually buy the one pound package of instant yeast and keep half in the fridge and the other half in the freezer. I never proof instant yeast. Recently I bought a new package of yeast and instead of instant it is regular yeast with a coarser grain. I don't bother to "proof it" but I do add the water and the yeast to my mixer first and give it five minutes to soften. I use all the various yeasts interchangeably. I don't make any adjustments. How much dry yeast is in 1/4 ounce envelope? About 2 1/4 teaspoons. How should I store yeast? Store unopened yeast in a cool, dry place, such as a pantry (or refrigerator). Exposure to oxygen, heat or humidity decreases the activity of the yeast. After opening, store in an airtight container in the back of the refrigerator, away from drafts. Use within 3 to 4 months; freezing not recommended. Can I use expired yeast in my recipe? For best results, buy and use yeast before the expiration date. Yeast loses its potency as it ages, resulting in longer rising times. Proof yeast to determine whether it is still active. How do I proof yeast to test for activity? To proof yeast, add 1 teaspoon sugar to 1/4 cup warm water (100 to 110°F). Stir in 1 envelope yeast (2 1/4 teaspoons); let stand 10 minutes. If the yeast foams to the 1/2 cup mark, it is active and you may use it in your recipe. RapidRise yeast loses its fast rising capabilities if dissolved in liquid, and will require two complete rises. Can RapidRise and Bread Machine Yeast be used in Active Dry recipes? Yes. Simply follow the One-Rise Method detailed on every package. For best results, add undissolved RapidRise or Bread Machine Yeast to dry ingredients first. Add liquids and fat heated to 120°to 130°F. To use the traditional Two-Rise Method, add sugar to water before stirring in Yeast Can Active Dry Yeast be used in RapidRise recipes? Yes, but with limitations. The Active Dry has larger granules and it is necessary to dissolve completely for the yeast to work. Therefore, Active Dry works best if dissolved in warm water (100° to 110°F). To use the electric mixer method, combine yeast with 1/4 to 1/3 of the flour and other dry ingredients. What is the difference between Instant Yeast, Bread Machine Yeast and RapidRise Yeast? Mainly names, but these are all the same yeast! Use interchangeably What is the difference between fast-rising yeast (RapidRise/Bread Machine Yeast) and Active Dry Yeast? RapidRise and Bread Machine Yeast are different strains than Active Dry Yeast. RapidRise and Bread Machine Yeast are grown with a higher level of nutrients and are dried to lower moisture content. The particle size of RapidRise and Bread Machine Yeast are finely granulated to allow complete hydration of the yeast cells during the mixing process. The Active Dry Yeast larger particle size should be dissolved in water to achieve complete hydration prior to adding to the mixer. In addition, RapidRise and Bread Machine Yeast contain ascorbic acid resulting in increased loaf volumes. How do I use Fresh Active Yeast? Fresh Active Yeast is the product that Fleischmann's has been manufacturing for over 130 years. It is also traditionally known as compressed or cake yeast. It has not undergone the drying process, so it does not need to be dissolved before use: soften the cake in warm water first OR simply crumble the yeast into dry ingredients (if directed by recipe). Fresh yeast requires two rises. Yeast is available in two different sizes: 0.6 ounces and 2 ounce household cakes How do I substitute dry yeast for Fresh Active Yeast? First determine the amount of dry yeast you will need. One .6 ounce cake is equivalent to 1 envelope of dry yeast. One 2-ounce cake is equivalent to three envelopes of dry yeast. Follow the directions on the package recommended for the type of yeast you substitute Can Active Dry Yeast be used in bread machines? Bread Machine Yeast is a fast-rising yeast specially formulated for bread machines. It is finely granulated to hydrate easily when combined with the flour. Ascorbic acid (vitamin C) is added to promote good loaf volume and structure. Active Dry Yeast may be used but may not yield optimal results. Can any dough be refrigerated? Any dough can be refrigerated for a few hours to inhibit rising if the leavening process is interrupted. Long refrigeration is not recommended unless specified in the recipe. For best results, choose recipes specifically formulated for the refrigerator. Refrigerator doughs have more sugar and less salt than regular dough to keep the dough viable in the refrigerator. Refrigerator doughs are particularly good for rich, sweet doughs, as less flour is used. Refrigerator doughs are typically not kneaded. They become stiffer and easier to shape after refrigeration. Can I freeze my dough? For best results, use only specially developed freezer dough recipes. Freezer dough recipes are high in yeast and sugar and low in salt. Bread flour is recommended. Other flours do not hold up well. Lean dough, such as pizza, freezes better than rich dough. How is freezer dough prepared? After kneading, flatten dough into a disk and wrap airtight, in a freezer-proof plastic bag for up to 4 weeks. When ready to use, thaw at room temperature or in the refrigerator. Once thawed, remove dough from bag; shape, let rise, and bake as directed. To shape before freezing, cover kneaded dough and let rest 20 minutes. Shape as desired and freeze as quickly as possible. Examples of freezer dough recipes in breadworld.com include: Cheese Coffee Cake Freezer Rolls Giant Pecan Sticky Buns Master Bread Dough Master Pizza Dough Can I rescue dough that does not rise? Dough can be 'revitalized' with a fresh sample of Active Dry or RapidRise Yeast. 1. For each envelope of yeast in the recipe, combine in a large, warm bowl: 1/4 cup lukewarm water (100° to 110°F), 1 teaspoon sugar and one envelope (2 1/4 teaspoons) of yeast. Stir to dissolve. 2. With an electric mixer, slowly beat in small (walnut size) pieces of dough until about 1/2 of the dough is mixed into the yeast. 3. With a spoon, stir in the remaining dough. Knead in just enough flour so the dough is not sticky. 4. Let rise, shape and bake as directed in the recipe. Should recipes be adjusted for high altitudes? Yes. But there are no exact rules for adjusting yeast breads at high altitudes. Altitude affects the ingredients and the entire breadmaking process. We suggest these general guidelines for baking above 3,000 feet. * Because atmospheric pressure is lower and leavening gases expand more quickly, yeast dough rises 25 to 50 percent faster at high altitudes. Begin checking the dough halfway through the rising time listed in the recipe. Continue to check frequently. * Flour tends to be drier and absorbs more liquid at high altitudes. Therefore, it is very important to store flour in an airtight container. * When mixing the dough, you may need less flour than called for in the recipe. To compensate, add flour slowly and work in only enough to make the dough easy to handle. Because recipes call for varying amounts of flour, there is no standard measurement for reducing flour. * If dough is slightly sticky during kneading, use greased instead of floured hands. This way, you won't knead in too much flour * Dough dries out faster at high altitudes. To prevent drying, grease or lightly oil the exposed part of dough (whether in a bowl, on a board, or in a baking pan) and cover with greased plastic wrap instead of a towel. * Baking temperature and time should not change at high altitudes, but check for browning at the shorter time listed and use traditional doneness tests * Just as dough dries out faster at high altitudes, so does the finished product. Store cooled bread in airtight plastic wrap, bags, or containers. * If you are using a bread machine at high altitude, refer to the manufacturer's instruction book. Since flour may dry out faster at high altitudes, you may need to adjust the ratio of liquid to flour. Experiment by reducing the amount of yeast, flour or sugar (yeast feeds on sugar), and/or adding liquid or a little gluten. Or try a shorter baking cycle, such as rapid bake, if available.

I use both Active Dry Yeast and a Fast-Rising Yeast (SAF-Instant) in the bread machine and for recipes I make by-hand. These yeast products are, and they are NOT, interchangeable, depending on it's application - just to complicate the issue for you. I tend to respect the type of yeast called for in a recipe. I also know when a recipe calls for Active Dry Yeast and I use a Fast-Rising Yeast, I should also reduce the amount by 25% or it will rise too quickly. This is especially important in a bread machine because the rise is TIMED, and you can find your bread dough pushing the lid off the bread machine because you've actually added TOO much yeast. The Fast-Rising Yeast products were originally used to make bread quicker by: -Omitting proofing the yeast in water/sweetener. You can cut 10-minutes off right there. You can add the yeast directly to a portion of the dry ingredients. (Don't forget you need the liquid to be warmer than when you proof yeast in water). The water cools quickly when it's added to a bulk amount of dry ingredients, so the warmer temperature is necessary to activate the yeast because it cools during the mixing. Side note... Because yeast has developed over the years, you can also add active dry yeast directly to the dry ingredients, you'll find many recipes that do so. You don't ALWAYS have to proof the yeast first. It's just another option in the world of bread-making. Just remember the temperature of the liquid will need to be higher (125-130-degrees F) than when you proof the yeast in water (100-110-degrees F). -Using a fast-rising yeast you can also omit the first rise. After kneading, you cover the dough and allow it to rest for 10-minutes before forming the dough. After your dough is formed, you allow it to proof to "double" as usual. If you happen to have a Zojirushi Bread Machine, you'll notice in the recipes in the user's manual they suggest one amount of yeast if you use Active Dry Yeast, and another (smaller) amount if you use a Fast-Rising Yeast, when you use the regular cycle. The same information is included in Beth Hensperger's book, "The Bread Lover's Bread Machine Cookbook". As the others have shared, a fast-rise is a destination to get bread done quicker, but not necessarily BETTER bread. I have an old recipe for 30-Minute Hamburger Buns and they literally take only 30-minutes from start to baked burger buns. It's enormous amount of yeast in ratio to the amount of flour (6-tablespoons to 10-1/2 cups whole wheat flour = 4 dozen hamburger buns) is what makes it work in 30-minutes. While I've used this recipe when time was an issue, I wouldn't have put the finished product in the County Fair because they just wouldn't stand up to Judging Standards. But the recipe works well for a huge bunch of teenagers over for Sloppy Joes on the spur of the moment. Heck, they'll eat ANYTHING!!!(LOL) For bread in a bread machine that is made on the Quick Cycle in one hour, you MUST use the fast-rising yeast (SAF-Instant, Quick-Rise, Rapid-Rise, or Bread Machine Yeast - which are all fast-rising yeast products), in order to get a loaf in 1-hour. Active Dry Yeast won't work properly on the Quick Cycle. If you ever need to test your yeast (especially if you buy in bulk and don't use it all that often): Use a 1-cup glass measuring cup. Fill it to the 1/4-cup line with warm water and add 1 t. sugar and 1-1/2 t. yeast. Wait 10-minutes. If your yeast is active it should be up to the 1/2-cup line. And always remember... Your bread dough rises according to the strength of the yeast, ambient temperature, and moisture --- NOT according to a clock. The bread dough that rises in 25-minutes in the summer in my kitchen can take 45-minutes in a cold winter kitchen. -Grainlady

King Arthur Flour pretty much sums up what I've heard. That is that you definitely can substitute (after all, yeast is yeast) and although some suggest you need to use a different amount, KA says what I've heard from a number of sources. It's not really worth changing the amounts. Experiment if you want to though. Don't let me stop you! Here's an excerpt: "You may substitute active dry yeast for the instant yeast called for in our recipes without making any changes in the amount; if the recipe calls for 2 teaspoons of instant yeast, use 2 teaspoons of active dry yeast. (The official word on instant yeast is that you can use 75% the amount of instant yeast to replace active dry yeast in a recipe, but we never bother with the conversion; we find it all tends to even out in the end.)" Did you know yeast will keep birds from nesting in horses' manes? "Yeast is yeast and nest is nest and never the mane shall tweet". (Oh go groan somewhere else!)

You didn't say how long you've had it or storage conditions or anything but assuming you got it recently and kept it properly I would have contacted them to give them the chance to make it right instead of rushing to give it bad reviews. Geez. Things happen. Most reputable vendors appreciate someone contacting them when something is wrong so they can make it right. Buying mailorder is risky in a lot of ways. How long does that package sit in the mail truck, sitting in the sun baking away? It's easily damaged. Could have been a defective batch. Could have been a number of things. Could be there was supposed to be a date on it and for some reason it didn't get stamped on there. We can't tell you, only the manufacturer can. Of course you should return it especially since it bothers you so much. I don't like getting defective things or things that don't work like I think they should. Not many people do. But at least be fair to them. Giving them no chance to rectify the problem and then giving them bad reviews is just plain wrong. How would you feel if you sold something to someone and they complained like that without giving you the chance to resolve an issue? Calm down. It's just some yeast!