Yeast for baking

Yeast is a useful ingredient in cookery. Yeast is used as a raising agent to make a dough mixture light with an 'open texture'. Yeast is a biological raising agent. It is a single cell living organism called 'bakers yeast' or saccharomyces cereviciae.

Yeast cells need the right conditions of warmth, moisture, food and time to ferment.  Yeast produces a gas during this process called carbon dioxide.  The gas aerates the dough mixture and makes it rise.  During baking in a hot oven the yeast cells are inactivated and the dough is set into the risen shape.

Yeast likes a temperature of around 35ºC to produce gas bubbles.  It uses the flour and some sugar as a food source. The proving process takes time.  It needs to happen before the baking when you put the shaped dough to rise in a warm place and wait.  You can tell if the yeast has done its work when the dough has doubled in size. 

Flat breads do not use yeast and that is why they are flat and less voluminous that leavened breads.  Soda bread uses another raising agent, bicarbonate of soda.

Yeast can be bought in the following forms as shown on the photo:

Left: Instant, easy-blend yeast Centre :Fresh bakers yeast  Right: Dried yeast - rehydrate to use

15g of fresh yeast can be replaced by 7g (a satchet) of fast action or easy blend yeast.

See how yeast ferments to produce gas bubbles after 5 minutes.

After 10 minutes:
After 15 minutes: 
Yeast is used to produce white bread.  Can you see the effect yeast has had on the dough?
Some breads have a different texture, here is Ciabatta, a bread from Italy that was developed to rival the wonderful French baguette.
Faults in bread can sometimes be seen.  Here in the photo below some yeast cells have clumped together producing gas to create a large hole in the loaf.
Here are a few examples of yeast used to make baked products, firstly Brioche, a sweet dough.
Danish pastries use yeast to raise the rich pastry dough.  You may have also eaten croissants that are produced in a similar way and have a very light, crisp open texture.
Stollen, a German traditional fruited bread with a marzipan centre is raised using yeast.
Pretzels made using yeast are strands of dough looped in a traditional way to form a knot shape.
Try baking with yeast. Get used to handling a dough containing yeast.  Temperature is very important throughout the preparation and the cooking. Yeast needs the dough mixture to be held around 28ºC to 30ºC to allow the carbon dioxide to be produced effectively. There are stages of making that are essential and some that are optional. Most yeasted mixtures require thorough initial mixing, optional proving of the whole dough, shaping and proving, followed by cooking until the crust is crusty and the crumb is soft.

Start with white bread rolls, pizza bases, cottage loaves, plaits and move on to sweeter mixtures for teacakes, hot-cross buns and then try enriched doughs, with added butter and eggs such as the brioche, stollen and Danish pastries. You will find all the recipes on the website.