Yeast: a closer look at the punch-packing ingredient behind beer and bread
When was yeast first discovered?
Humans, as far back as 5000 years, likely stumbled upon yeast by accident, not knowing how fermentation worked but enjoying its benefits none the less until, thanks to champion scientist Louis Pasteur in 1857, fermentation entered the realm of science and an advancement in brewing and baking was made possible.
So how does yeast work?
Yeast is a living single-cell organism with a rather sweet tooth. When combined with a starch or sugar, yeast literally consumes the sugar and spits out carbon dioxide and alcohol as waste products. This process is called fermentation.
Fortunately for brewers and bakers, these waste products are not waste at all, but rather vital contributors to the success of the end product. Carbon dioxide gives beer its carbonation and bread – its air pockets, which results in the light, fluffy texture. Alcohol released into bread burns off while baking, but definitely sticks around to add value to beer. Interestingly, yeast also contributes lovely flavour to both beer and bread and, depending on which strain of yeast used, these flavours can be notably different.
Different types of yeast
Yeast is pretty versatile. From commercially produced to naturally propagated, you’ll find it in various shapes and forms, to suit both your lifestyle and interest level.
For specialist bakers
Before the production of commercial yeast, brewers utilised air-borne yeast while bakers benefited from yeast found naturally in flour. Specialist bakers today still rely on this natural method to create sourdough breads packed with flavour – some even keep the same yeast starter alive for years because the unique flavour profile gives their bread a signature style.
For the home baker
For home bakers, the easiest and quickest yeast source is dried baker’s yeast, available in little sachets at your local supermarket.
Fresh yeast is another good option although, because of its short shelf life, it can be hard to find. It looks like a small block of butter and searching for it at a health shop is probably your best bet.
For the home brewer
Commercial brewer’s yeast is a different strain to baker’s yeast and has characteristics specifically suited to brewing. There are two main types of brewing yeast, used to either brew ales or lagers.
For the health fundis
Then there’s also a version of brewer’s yeast used as a nutritional supplement because it is so rich in B vitamins and minerals.
4 tips for getting the best from yeast when baking bread
Keep these few tips front of mind when baking with yeast and the results you get will be happiness–producing:
- Use warm not boiling water to ‘proof’ or test if the yeast is active. Yeast dies when heated to between 55°– 60° C. This kind of heat is necessary when you’re baking bread in the oven, but not when you’re wanting the dough to rise.
- Give yeast enough time to work on the flour before baking. At minimum, allow the dough to rest for an hour but if you can plan ahead and leave it overnight, you’ll get even better results. It’s quite a marvellous thing to watch the ball of dough puff up and virtually double in size.
- Salt slows down the growth of yeast, so when making bread or pizza dough, add salt to the flour rather than to the yeasty water.
- Knead the dough. By doing this, you’ll make sure the yeast is evenly distributed and your bread has an even rise.
We hope you now have a newfound appreciation for a little ingredient that is arguably baking and brewing’s most impactful.