# What are the emissions from making baker's yeast?

Canonical: https://senseible.earth/answers/yeast-plant-fermentation-co2-and-energy

Yeast is grown on molasses in aerated fermenters. CO2 released by the yeast comes from sugar, so report it separately as biogenic. Fossil emissions come from aeration blowers and cooling (electricity), steam for sterilising and drying, and effluent treatment.

## Where the energy goes

- Air blowers and compressors for aeration.
- Cooling to hold fermenter temperature.
- Steam for sterilising and for drying yeast.
- Effluent treatment.

## Effluent

Anaerobic effluent treatment can release methane, which counts in Scope 1 unless it is captured and burned.

## What Senseible does here

Senseible reads fuel invoices and electricity bills and applies IPCC 2006 factors and the CEA grid factor (0.710 kg CO2 per kWh), so you can compare Scope 1 and 2 before and after a change from the documents themselves.

- [Fermentation API footprint](https://senseible.earth/answers/fermentation-api-carbon-footprint)
- [Grain ethanol distillery](https://senseible.earth/answers/grain-ethanol-distillery-co2-per-litre)

Sources: [2006 IPCC Guidelines for National Greenhouse Gas Inventories](https://www.ipcc-nggip.iges.or.jp/public/2006gl/), [GHG Protocol Corporate Standard](https://ghgprotocol.org/corporate-standard), [GHG Protocol standards, including the Product Standard](https://ghgprotocol.org/standards)

Last reviewed 2026-10-22.