What is Yeast?
It surprises some people to discover that yeast in its natural form is a living organism. It is a single-cell organism that is found naturally on plants and even on animals and people. Baker’s yeast differs slightly from brewer’s yeast, and it is the former we are talking about here.
As a living organism yeast needs food to survive. It finds this food in the form of sugar and starch, which it ingests and converts into ethanol (alcohol) and carbon dioxide (CO2). In baking, this is the process – known as fermentation – which allows the bread to leaven or rise, which simply means it expands and becomes lighter and less dense.
Yeast has been used for many centuries – there are records of it being used in Ancient Egypt – yet it is unknown how they came to understand its properties for baking and brewing. Which is the best type of yeast for bakers?
The Choice of Yeast Types
Commercial bakers may draw from the same source of yeast, having propagated it using a sourdough recipe. They simply keep the yeast in the perfect conditions and use the prescribed among of live yeast when required. For home use, there are various options that make it easier to obtain yeast for baking all year around.
Fresh Yeast – reckoned by most bakers to be the best choice, you can find fresh yeast at many stores. Ask the bakery department in your local store if you can have a small amount, and many will be happy to give or sell you some. It should be creamy but firm and moist, and not dark and crumbly, and will give the best results and flavour. The problem lies in keeping fresh, live yeast healthy and active, as it will eventually go off and be unusable.
Dried Yeast – dried, granular yeast is commercially available from your local store, and is far more convenient than fresh yeast. You will need to ‘proof’ the granules before using. Simply add some to warm water with a little sugar – follow the instructions on the packet for the right amounts – and if active, the solution should start to froth. This is good to use but if it does not froth, you need some new yeast!
Yeast is quite amazing when you consider what it does to the dough. Without it, we would be eating ‘unleavened bread’ which does not have the same properties as bread that has risen. Take care to find the best source of fresh baker’s yeast or look in your local store for the dried variety, and you’ll enjoy baking bread to the same quality as the commercial bakeries. It’s all down to yeast, so make sure you get the best.