Yeast Conversion Guide: Instant, Active Dry and Fresh

The three types

These ratios follow the substitutions published by the major yeast manufacturers. The yeast converter does the arithmetic for any amount, in grams, teaspoons or packets.

Packet sizes

The standard US packet holds 7 grams, which is about 2¼ teaspoons. That size exists because it is roughly what one loaf of ordinary sandwich bread wants, which is why so many American recipes are written around "one packet".

UK and European sachets are usually 7 g too, though 5 g and 11 g sachets both exist. If your recipe says one sachet and yours is a different size, weigh it rather than assuming.

One 7 g packet of active dry is equivalent to:

Converting between them in practice

Active dry to instant. Multiply by 0.75. A recipe wanting 2 teaspoons of active dry needs 1½ teaspoons of instant. You can also skip the proofing step and add it to the flour directly.

Instant to active dry. Multiply by 1.33, and dissolve it in some of the recipe's warm liquid first with a pinch of the sugar. Give it ten minutes to foam before mixing.

Fresh to dried. Divide by 2.5 to get active dry, or by about 3.3 to get instant. A 42 g block of fresh yeast is roughly 17 g of active dry or 12.5 g of instant.

Yeast by the teaspoon

Fresh yeast does not measure sensibly by volume — it is a moist solid that packs differently every time. Weigh it.

Checking your yeast is alive

Yeast dies, and it dies silently. There is no point discovering this after you have committed a kilo of flour.

Dissolve half a teaspoon of yeast and a pinch of sugar in about 60 ml of water at roughly 40 °C — warm to the touch, not hot.

Wait ten minutes.

What slows yeast down

Salt. Around 2% of the flour weight is the standard — 10 g of salt for 500 g of flour. Much more and the rise drags badly; much less and the loaf tastes flat and over-ferments. The old advice about keeping salt and yeast apart in the bowl matters mainly if they sit together for a while before mixing; adding them to opposite sides of the flour is plenty.

Sugar. Small amounts feed yeast. Large amounts — enriched doughs like brioche, cinnamon rolls, panettone — draw water away from the yeast and slow it down. That is why those recipes use more yeast and still take longer.

Fat. Butter and oil coat the flour, softening the crumb but slowing gluten development. Enriched doughs need more time, not more heat.

Using less yeast on purpose

Most recipes call for more yeast than the loaf needs, because more yeast means a faster rise and a shorter recipe. Flavour runs in the opposite direction.

Almost everything that makes bread taste like bread develops during fermentation, not baking. Halving the yeast roughly doubles the rise time and gives those flavours time to form. A dough with a quarter of the usual yeast, left in the fridge overnight, is noticeably better than the same dough pushed through in two hours.

This is worth knowing when you convert a recipe: if your bread is technically fine but bland, the answer is usually less yeast and more time, not a different flour.

Storage

Opened yeast keeps for months in an airtight container in the fridge or freezer, and only weeks in a warm cupboard. It does not need defrosting before use — take it straight from the freezer into the flour.

Fresh yeast is the exception: it keeps for about two weeks in the fridge, and it freezes poorly. Buy it for a specific bake.

For the amounts themselves, use the yeast converter. For everything else in a bread recipe, the grams to teaspoons converter handles salt and small quantities, and the ingredient index has flour densities.

Frequently asked questions

How much instant yeast replaces active dry?

About 25% less. One teaspoon of active dry becomes ¾ teaspoon of instant. By weight, multiply the active dry amount by 0.75.

How much is one packet of yeast?

7 grams, which is about 2¼ teaspoons of active dry or instant. Some UK sachets are 5 g — check the packet.

How much fresh yeast replaces a packet of dried?

About 17 g of fresh yeast does the work of one 7 g packet of active dry, because fresh yeast is mostly water.

Do I have to proof instant yeast?

No. Instant is milled finer and mixes straight into the dry ingredients. Proof it only if you want to check it is still alive.

What happens if I use too much yeast?

The dough rises fast, then collapses, and the bread tastes yeasty and one-dimensional. Most of bread's flavour develops during a slow fermentation, so rushing it costs flavour.