ChoJin’s Quarter

My first post about cooking. I’ll start with the yeast since I’m planning to write quite a bit about bread making and yeast-ed pastry (such as French croissants).

Buying, storing and using yeast can be confusing at first: there are different types of yeast and each one of them call for a different way of handling. Thus, I’ll try to give a quick overview without going into the usual details about how they are made.

Yeast Types

Instant Yeast

Instant yeast, sometimes called rapide-rise or fast rising yeast , is the most common type of yeast you can buy in a store. Because of the method by which it is produced, instant yeast is 25% more concentrated than active dry yeast and 3 times (300%) more than fresh yeast. Moreover, instant yeast doesn’t need to be hydrated beforehand, because it comes in such very small grains that they instantly hydrate when mixed with the ingredients. It is therefore very convenient to use and can be kept for months in the refrigerator in an air-tight container.

One special note though: be careful about its name, as it is sometimes labeled “rapide-rise active dry yeast”, not to be confused with “active dry yeast”. The size of the grains makes it easy to recognize but they often come in an opaque packet, so just be careful when buying it.

Active Dry Yeast

Active dry yeast, sometimes called “levure de boulanger” in France, comes in larger grains that the instant yeast. Because of that it needs to be hydrated first. And since they are less concentrated than instant yeast, you’ll need to use slightly more yeast than with instant yeast.

Fresh Yeast

Fresh yeast, sometimes called a “cake”, is the yeast usually used by bakeries. It usually comes as a pound compressed cake and it is very perishable. Correctly wrapped in a plastic wrap, it can be kept only up to 2 weeks in the refrigerator, although you can keep it for a couple of months in the freezer. The freezer won’t kill the yeast if correctly wrapped and stored in a container. I usually cut the block of fresh yeast in cubes, wrap them in plastic individually and store them in a plastic container in the freezer. I find this very convenient as it is then easy to just take one cube at a time when needed.

People often say that fresh yeast gives a better taste than instant yeast. I didn’t experiment a lot yet, but I didn’t find the difference to be extremely noticeable. It doesn’t exactly taste the same, but not having fresh yeast won’t ruined your recipe (for trouble shooting, if you have trouble reproducing the taste of your favorite pastry or bread, check the brand of the flour and/or the fermentation/rising time, which gives 80% of the taste of a french baguette for example). So feel free to substitute instant yeast to fresh yeast.

Fresh yeast can be tricky to find and buy. It used to be in the refrigerator compartment, but can hardly be found there anymore. I finally manage to find some though. The trick is to ask to the bakery compartment in stores. I tried at Safeway but they didn’t have or were not selling it, then I finally manage to get some at Cosentino’s market (a sort of Safeway supermarket but with higher quality stuff), on Bascom Ave in San Jose, CA. The lady sold me a big block of fresh yeast for $5. I therefore now have yeast for months, and for a lot cheaper than instant yeast

Wild Yeast

Wild yeast is the type of natural yeast which lives everywhere around us. We’ll come back on this type when we’ll talk about sourdough bread and the “pain de campagne”.

Proofing the yeast

Proofing the yeast has two purposes: activating the yeast and making sure the yeast is not dead. Proofing is usually not necessary with instant yeast, although you can if you think your yeast might be dead.

To proof the yeast just add some water (not too hot, as it could kill the yeast), some flour and possibly a little bit of sugar (not too much) if the recipe calls for it. Mix to dissolve the yeast, and let proof for 10min. After 10min, if the yeast is not dead, you should see a foam and some bubbles forming at the surface.

By the way, a side note to prevent from killing your yeast: yeast hates salt. Never put the yeast directly in contact with the salt. If you are using a bread machine, put the yeast and the salt in two opposites corners. When kneading by hands or using an electric mixer, I usually start mixing without the salt and add the salt after the yeast is fully incorporated. Also, if you feel that your yeast is not rising enough, and you don’t understand why, try using purified water (not mineral water, as it usually contains salt). Your tap water could contain too much chlorine (as in mine apparently).

Conversion formula, equivalence and substitution

Often recipes call for a specific kind of yeast. It’s fairly easy to substitute a kind of yeast for another using the following formula:

100% fresh yeast = 40 to 50% active dry yeast = 33% (or 40% for home baker at lower temperature) instant yeast.

In other words, if the recipe calls for instant yeast:

• multiply by 1.25 for active dry yeast equivalent
• multiply by 3 for fresh yeast equivalent

if the recipe calls for active dry yeast:

• multiply 0.8 for instant yeast equivalent
• multiply by 2 for fresh yeast equivalent

if the recipe calls for fresh yeast:

• divide by 3 for instant yeast equivalent
• divide by 2 for active dry yeast equivalent

Conclusion

That’s it for the yeast! We are now ready for the upcoming delicious recipes . I hope you’ve found this post useful. Any comments and corrections are welcome

Sources and Links:

The Bread Baker’s Apprentice, Mastering the art of extraordinary bread, by Peter Reinhart. (by Amazon.com)

Yeast - Fleischmann’s Instant (by Amazon.com)