Buying yeast for pizza

Short answer

Instant yeast is the most convenient: mix it straight into the flour and store the opened pack in the fridge or freezer. Active dry yeast works much the same, though some recipes use a little more of it. Fresh yeast is traditional in many pizzerias but perishable. A sourdough starter is a different system that takes upkeep and gives acidity. Whatever you buy, keep it cool and airtight and check it is alive before relying on it.

Instant, active dry and fresh

Instant yeast is fine dried granules that can go straight into the flour. Active dry yeast has larger granules and was traditionally dissolved in warm water first; King Arthur and the manufacturer Red Star treat it as interchangeable with instant by weight, while many recipes still use roughly 1.25–1.5 times as much active dry as instant. Fresh (compressed) yeast is moist and perishable; a common rule of thumb is about three times the weight of instant.

For pizza, which type you use matters less than the dose, time and temperature. Small quantities are easiest to measure accurately in dried yeast; doughs for long cold ferments may use well under 1% of the flour weight, so a scale that reads to 0.1 g helps. The yeast and fermentation basics explainer covers dosing, and the dough temperature tool helps you hit a target dough temperature.

Freshness and storage

Yeast loses activity over time, faster once opened and when warm or damp. Manufacturers typically advise keeping unopened dried yeast cool and dry, and storing opened yeast airtight in the fridge or freezer, using it within a few months; some products give shorter windows, so follow the pack. Fresh yeast keeps for a much shorter time in the fridge.

If a dough rises unusually slowly, old yeast is a likely cause. Proofing a pinch in warm water with a little sugar shows whether yeast is alive: it should foam within roughly 10 minutes. The troubleshooting page on yeast that does not foam covers what to check.

Sourdough starter

A sourdough starter is a culture of wild yeasts and lactic acid bacteria that you maintain with regular feeding, or obtain from another baker. It ferments more slowly and less predictably than commercial yeast and adds acidity and flavour. It cannot be converted from dried yeast by a fixed factor, because starters vary in strength. It is a choice about flavour and process, not a better or worse yeast; the sourdough starter method page describes how it is used in pizza dough.

What to look for

• Type (instant, active dry, fresh)

  Affects convenience, shelf life and how much you use, more than the finished pizza.

  Check: The type on the pack; instant is the simplest for most home cooks. Adjust quantities when switching types.

• Best-before date and storage after opening

  Yeast activity declines over time, especially once opened.

  Check: The date on the pack and its storage instructions; date the pack when you open it and keep it airtight and cold.

• Pack size

  Pizza dough uses small quantities, so a large pack may lose activity before it is used.

  Check: Buy an amount you will use within the maker's opened-storage window, or freeze the surplus.

• Additives

  Some dried yeasts include emulsifiers or dough improvers, which are not needed for pizza.

  Check: The ingredients list; plain yeast is all a pizza dough needs.

Sold harder than it matters

• Fresh yeast for 'better flavour'. Fermentation time and temperature are well documented to shape dough flavour; PizzaHQ has found no good evidence that the form of commercial yeast does so at an equivalent dose and schedule. Fresh yeast is also the hardest to keep active.

PizzaHQ does not test, rank or recommend yeast brands. Manufacturer guidance is cited only for how to use and store their type of product; this guide is not based on products PizzaHQ has tested.

Common misconceptions

“Instant yeast must be dissolved in water first.”

It can be mixed directly into the flour. Dissolving it is optional, and proofing is mainly a way to check old yeast is alive.

“Pizzerias' flavour comes from using fresh yeast.”

Flavour comes mainly from fermentation time, temperature and flour. Pizzerias may choose fresh yeast for tradition, habit or cost; that choice is not evidence that the yeast form drives flavour.

What this page cannot tell you

Yeast conversions are approximations and sources disagree; storage windows vary by product and maker. This page gives no doses for particular schedules — use the fermentation schedule and dough temperature tools. PizzaHQ has not tested any yeast product.

Related

Evidence

• Active dry vs. instant yeast: Why we prefer instant — King Arthur Baking Company
• Saf-instant Red Yeast — Red Star Yeast (Lesaffre)
• How do I bake with fresh yeast? — King Arthur Baking Company
• Red Star Active Dry Yeast 4-ounce jar (storage guidance) — Red Star Yeast (Lesaffre)