Yeast should make your dough rise, not raise your blood pressure.

One of the most common questions home bakers ask is: “My recipe says fresh yeast, but I’ve got dried yeast, can I still use it?” Or: “The packet says instant yeast, but the recipe tells me to dissolve it in warm sugar water first, what should I do?”

The good news is that most baking yeasts can be swapped, provided you know what type you have, how much to use and how it should be added to the dough.

Quick answer

  • Organic dried yeast sachets are convenient for most home bread recipes. Our 9g sachets should be mixed with the flour, not dissolved in water.
  • Instant yeast goes straight into the flour or dough. It does not need dissolving first.
  • Organic fresh yeast is moist, perishable and should be kept chilled.
  • Osmotolerant yeast is useful for very sweet or enriched doughs.
  • Warm water means body temperature, not hot. Aim for pleasantly warm, around 37°C, not 50°C.
  • Foam is not the whole story. Yeast can foam naturally as it releases carbon dioxide, but lack of foam does not automatically mean the yeast is dead.

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Yeast conversion guide

If your recipe asks for one type of yeast and you have another, this table will usually get you close. Treat it as a practical guide rather than a rule that must be followed to the gram.

Recipe asks for Practical replacement What to expect
Fresh yeast for a standard 500g flour dough 1 × 9g organic dried yeast sachet A convenient swap for everyday bread. Watch the dough rather than the clock.
7g dried yeast 1 × 9g organic dried yeast sachet Use the whole sachet for convenience. The dough may rise a little faster.
5g instant yeast 5g instant yeast, or 1 × 9g organic dried yeast sachet if that is what you have Using the 9g sachet may make the dough more active, so keep an eye on the rise.
A very slow or overnight dough Use less yeast, especially if using a larger pack Long fermentation usually needs less yeast, not more.

Useful rule of thumb:
Fresh yeast is usually used at roughly 2 to 3 times the weight of dried yeast, but recipes vary. For home baking, a 9g dried yeast sachet is a sensible amount for many doughs made with around 500g flour.

Dough temperature, flour type, fermentation time, salt, sugar, fat and hydration all affect how quickly dough rises. Use less yeast for long, slow fermentation and more only where the recipe, timing and dough style call for it.

The main types of baking yeast

Organic dried yeast

Organic dried yeast is a convenient option for everyday bread making. Our small 9g sachets are designed to be mixed with the flour. They should not be dissolved in water first.

If you are using a larger pack, keep it sealed, cool and dry once opened. Decanting into an airtight container can help protect it from air and moisture.

Instant dried yeast

Instant yeast has fine particles and is designed to be mixed straight into the flour or dough, without dissolving first.

This is the yeast that often causes confusion. If you put instant yeast into warm sugar water and expect a foamy head, you may be testing it in a way it was not designed for.

Foam can form naturally when yeast starts fermenting and releasing carbon dioxide, but the amount of foam you see in a cup is not a reliable test for every yeast. The LeSaffre and Agrano yeasts we stock do not list added foaming agents, so they should be judged by how they perform in dough, not by whether they foam in sugar water.

Active dried yeast

Some recipes use the phrase active dried yeast to mean a granular dried yeast that is dissolved or hydrated before being added to the dough.

If your yeast packet tells you to dissolve it first, use water at about body temperature, around 37°C. It should feel pleasantly warm, not hot. Water at around 50°C is too hot and may damage the yeast.

If your packet tells you to mix the yeast with the flour, follow the packet rather than the recipe’s generic instruction to dissolve yeast in water.

Organic fresh yeast

Organic fresh yeast is moist, soft and perishable. It is often favoured by bakers because it disperses well in dough and gives reliable fermentation when used fresh.

Keep it refrigerated and use it promptly. Cut off only what you need, then rewrap the rest and return it to the fridge. Try to minimise skin contact with the yeast you are storing, as handling can introduce moisture and microorganisms that may encourage mould.

Fresh yeast can be crumbled directly into flour or dissolved into the recipe liquid, depending on the method. It does not need to be tested in sugar water before every use.

Osmotolerant yeast

Osmotolerant yeast is designed for sweet or enriched doughs. Sugar is greedy for water, and in doughs such as brioche, panettone, doughnuts and sweet buns, sugar competes with the yeast for the water it needs to work.

Ordinary yeast can become sluggish in these doughs. Osmotolerant yeast copes better in high-sugar doughs and can give a more reliable rise.

Pizza yeast

Pizza yeast is usually chosen for pizza-style doughs, where extensibility, handling and reliable fermentation are important. It is useful for pizza bases, flatbreads and doughs where stretch matters, but it is not automatically the best choice for every loaf of bread.

Do I need to dissolve yeast in warm sugar water?

No, not unless your yeast packet or recipe specifically asks you to.

Some older recipes tell you to add yeast to warm water with sugar and wait for it to foam. That can be useful for some active dried yeasts, but it is not a universal rule.

Foam is usually produced naturally as yeast ferments and releases carbon dioxide. However, lack of foam does not automatically mean the yeast is dead. It may simply be the wrong test for that yeast or that method.

The LeSaffre and Agrano yeasts we stock do not list added foaming agents. In practice, the dough is the better test: does it ferment, expand and become aerated over time?

  • Organic dried yeast sachets should be mixed with the flour. Do not dissolve them in water.
  • Instant yeast should be mixed straight into the flour or dough. It does not need frothing.
  • Active dried yeast may need hydrating first if the packet says so.
  • Organic fresh yeast can be crumbled into flour or dissolved into the liquid, depending on the recipe.

If you do need water for dissolving or hydrating yeast, use water at about body temperature, around 37°C. It should feel pleasantly warm, not hot.

Does frothing prove my yeast is alive?

It can be a clue, but it is not the whole story.

A foamy cup of yeast mixture suggests activity, but a lack of foam does not always mean the yeast is useless. It may depend on:

  • the type of yeast;
  • how much yeast was used;
  • the water temperature;
  • whether sugar was added;
  • how long you waited;
  • whether the yeast was designed to be mixed directly into dough.

Do not judge all yeast by the sugar-water test.

  • Instant yeast does not need dissolving first.
  • Our organic dried yeast sachets should be mixed with flour, not dissolved in water.
  • Foam can form naturally, but lack of foam does not automatically mean the yeast is dead.
  • Warm water means body temperature, around 37°C, not hot water.
  • The real test is whether the dough ferments and rises.

The best test is usually the dough itself: does it ferment, expand and become aerated over time?

Why is my dough rising slowly?

Slow dough is not always caused by dead yeast.

Common reasons include:

  • the room is cold;
  • the dough is in a draught;
  • the bowl is cold;
  • the dough water was cold;
  • the recipe uses very little yeast;
  • the dough contains lots of sugar, butter, eggs or fat;
  • the dough has a long fermentation schedule;
  • the salt was added directly onto the yeast in a concentrated patch;
  • the yeast is old or has been poorly stored.

If the dough is slowly expanding and becoming gassy, it is probably alive. It may simply need more time.

When should I use osmotolerant yeast?

Use osmotolerant yeast for doughs with a high sugar content.

Examples include:

  • brioche;
  • sweet buns;
  • enriched doughs;
  • doughnuts;
  • panettone-style doughs;
  • festive breads with sugar, fruit and fat.

In these doughs, ordinary yeast may still work, but it can be slower and less reliable. Osmotolerant yeast is better suited to the conditions.

If a dough contains only a small amount of sugar, ordinary instant or active dried yeast is usually fine.

Can I use pizza yeast in ordinary bread?

Often, yes, but it depends what you are trying to make.

Pizza yeast is intended for pizza-style doughs and may be chosen for dough handling, stretch and extensibility. It can be useful for pizza bases and similar doughs.

For a standard loaf, instant or active dried baker’s yeast is usually the more straightforward choice. If you only have pizza yeast and want to make bread, you can often still bake with it, but expect the dough to handle slightly differently from a recipe written for ordinary bread yeast.

How should I store yeast?

Yeast is alive, so storage matters.

Organic fresh yeast

Keep organic fresh yeast refrigerated and use it promptly. Keep it well wrapped or sealed so it does not dry out.

When cutting a portion from a larger piece, use a clean knife and clean hands, and avoid unnecessary skin contact with the yeast that will be stored. Handling can introduce moisture and microorganisms that may encourage mould.

Do not leave fresh yeast sitting in a warm kitchen for long periods.

Dried yeast before opening

Keep unopened dried yeast somewhere cool, dry and away from direct heat.

Dried yeast after opening

Once a vacuum pack or larger pack is opened, air and moisture become the enemies.

For best results:

  • transfer opened dried yeast to an airtight container, or reseal the pack very carefully;
  • keep it cool and dry;
  • avoid letting condensation get into the container;
  • use it steadily once opened.

For organic yeasts, follow any storage guidance on the pack or product page. If freezing is not recommended, do not freeze it.

Common yeast problems

Problem Possible explanation
My yeast did not foam in sugar water It may not need to. Instant yeast and our organic dried yeast sachets are mixed into the flour. Foam can form naturally, but lack of foam is not a reliable test for every yeast.
My dough has not risen Give it more time, especially if the room is cool. If nothing happens after several hours in a warm place, the yeast may be old, damaged or under-used.
My bread tastes too yeasty You may have used too much yeast or rushed the fermentation. Try using less yeast and giving the dough more time.
My sweet dough is very slow That is normal. Sugar, butter and eggs slow fermentation. Try more time, a warmer spot, or osmotolerant yeast.
My dough rose too quickly Use less yeast next time, use cooler water, or ferment the dough somewhere cooler.

Final thoughts

Yeast is more flexible than it first appears. The important thing is to know which type you have and how it likes to be used.

If your recipe calls for one yeast and you have another, you can usually convert it. Just remember:

  • our 9g organic dried yeast sachets are designed to be mixed with flour;
  • instant yeast goes straight into the dough;
  • active dried yeast is only dissolved first if the packet says so;
  • organic fresh yeast is perishable and should be kept chilled;
  • sweet doughs may benefit from osmotolerant yeast;
  • storage matters once dried yeast has been opened;
  • the real test is how your dough ferments, not whether yeast foams in sugar water.

Once you understand those basics, yeast becomes much less mysterious, and your dough will be better behaved for it.