What Types of Yeast Are There And How To Convert Them?

/ / / What Types of Yeast Are There And How To Convert Them?
what yeast is right for my bread

There are many types of yeast available to home and professional bakers and knowing which one to use can be overwhelming. Each type can be used interchangeably, you just need to know how to convert the recipe and the activation technique required – if any.

The ones we are going to cover in this post are Instant Dried, Dried Active, Fresh yeast and SAF. So you’ll be able to resolve the fresh yeast vs dried yeast dilemma!

If you are looking at sourdough or using yeast to build preferments, check my guide to leavains.

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What does yeast do?

Yeast is a levain, and it’s the most recognised one in bread making. A levain is an active agent that’s added to a dough recipe to create gas and to make it rise.

Yeast respires when fed by the simple sugars found in the flour creating carbon dioxide and ethanol. The gas gets trapped in the gluten structure formed from the flour and raises the loaf.

The ethanol and organic acids which are also created during the dough fermentation process mature the doughs flavour and handling properties.

Yeast conversion table

Fresh Yeast Active Dry YeastInstant YeastOsmotolerant Yeast
30 grams13.2 grams10 grams9.6 grams
10 grams4.4 grams33 grams32 grams
5 grams2.2 grams16.5 grams16 grams
3 grams1.3 grams1 gram0.95 grams

Fresh yeast

Often referred to as “Bakers Yeast” or “Compressed yeast”, this is the simplest form of yeast. It’s derived from the yeast cream where it’s then filtered and compressed into blocks that are the same size as a house brick.

Fresh bakers yeast


It’s fast to act and requires no activation – removing a variable. Bakers yeast is the benchmark for all other yeast types and generates a slightly sweeter flavour. Artisan varieties are available which operate at cooler fermentation temperatures.

Shelf life

Kept wrapped it will stay fresh for 2- 4 weeks which makes it great to use commercially but weekend home bakers may struggle to use a portion without it going out of date.


No activation is required – add it straight to the dough.

Where to buy

Block size are wrapped in wax paper and sold in 800g or 1kg weights. You can buy cases containing around 12-20 blocks online, or for smaller amounts, I pop into my local supermarket or bakery.


Fresh yeast is 66-69% water making a slight adjust in the water levels required.

Active dried yeast

Manufactured by removing the water from fresh yeast, Active Dried Yeast is the most popular yeast for home bakers. It’s not as fast to ferment as fresh yeast. Active dried yeast requires activation before use, but is cheaper than instant yeast and has a much longer shelf life compared to fresh.


A little slower to activate which can be preferred by artisan bakers wishing to develop the gluten in the dough.

Shelf life

Once opened a tin of dried yeast states it must be used within 30 days yet I keep mine for much longer without any issues.


Dried active yeast has to be activated in warm water for 6 – 10 minutes. Ideally, a temperature of 41-46C (105-115F) is used.

Where to buy

Readily available at supermarkets and online, dried active yeast is the most common levain available.


To convert recipes from fresh yeast you should multiply by 0.44. Though most people will simply half the amount of fresh!

Instant fast-action yeast

Another form of dried yeast that uses a different method of manufacturing than dried. It works quickly, is suitable for bread machines and offers some enhancements to the dough. Though, instant yeast is double the price of active dried yeast.


Its small, dehydrated vermicelli get to work rapidly, sometimes it’s so quick the dough becomes gassy during mixing! The use of ascorbic acid included incorporates oxygen to increase the strength of the gluten during mixing.

Shelf life

Like Active dried, it should be used within 30 days of opening – but seems to last up to a year in the fridge.


No need for activation, it can go straight into the dough with the dry ingredients.

Where to buy

Available in most supermarkets and easy to find online.


A lot of people make the mistake of thinking they can use Active dried and Instant yeast interchangeably. But it’s a mistake to do this as instant is almost 50% powerful. To convert a recipe from fresh yeast, multiply by 0.33.

Osmotolerant yeast (SAF)

This yeast is designed for use in doughs that have high quantities of sugar in them. It is expensive, but for sweet artisan breads, it is the most reliable option.


Its make up works against osmotic pressure to allow the yeast to feed in conditions where it would otherwise struggle. Can reduce mixing time by 10-30% compared to fresh yeast.

Shelf life

It should be used within 30 days of opening, but can last 2 years still in its container.


No need for activation, it can go straight into the dough with the dry ingredients.

Where to buy

There are two versions of Osmotolerant yeast available, Bruggeman Instant brown (SD or “Sugar Dough”) and SAF – Instant gold. They are only available online from bakery supply specialists.


The activity of this yeast is 10-20% higher in sweeter doughs. For this type of bread it is common to use high levels of yeast, so using 1-3% bakers percentage is popular.

Liquid yeast

This is the yeast cream that is used in big commercial warehouses. It’s the purest form and doesn’t require any activation. It does contain more water and can be poured into the mix, replacing some of the water content.

how to bake bread

If you think you need liquid yeast, you probably know more about it than I do so I won’t comment any further!

Which brand of yeast do I choose?

Your yeast choice is going to impact your bread quality. I would choose either a reputable brand or a where bakers yeast is readily available at the quantities you use and use the same one in all your breads.

If you find a problem in a recipe then experiment with another brand. Being great at bread baking has a lot to do with maintaining consistency, having too many variables makes it harder

Need a recipe? Try the beginner’s bread recipe for a simple yet delicious homemade loaf.

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