Climate risks to flour performance explained
- Elevated CO₂ reduced bread volume by an average of 4.1% in field trials involving 10 winter wheat varieties
- Responses differed between varieties, suggesting breeding and selection could help preserve baking quality
- Bakers and millers need to assess flour against production performance alongside purchasing specifications and price
- Further trials across locations, seasons and applications are needed to establish how widely the findings apply
Bakeries already adjust to differences between flour deliveries, but changing growing conditions could make it harder to maintain the same loaf quality without further changes to recipes or production settings.
New research found that bread volume fell by an average of 4.1% when wheat was grown under elevated carbon dioxide, raising concerns about how flour will perform as atmospheric conditions change.
The study, led by the Leibniz Institute for Food Systems Biology at the Technical University of Munich, examined 10 winter wheat varieties and found that elevated CO₂ changed their protein composition and reduced baking quality. The response differed between varieties, suggesting that wheat selection could help protect the characteristics bakers need.
Protecting harvest volumes therefore addresses only part of the industry’s climate challenge. Millers and manufacturers also need wheat that delivers the dough behaviour and finished products their customers expect, without leaving the bakery to absorb an increasing burden of adjustment.
When changing wheat reaches the mixing bowl
A smaller loaf from the same recipe presents a practical problem for a bakery supplying products to an agreed size and appearance, particularly if restoring the expected result requires changes to ingredients or production settings.
In the experiment, published in Food Chemistry, researchers grew wheat under realistic field conditions at ambient carbon dioxide averaging around 450 parts per million and an elevated concentration of 546ppm. Alongside the reduction in bread volume, total grain protein fell by an average of 4.7%.
“Our results also showed that the reduced concentration of gluten proteins was associated with poorer baking quality,” said Sabrina Geisslitz, lead researcher and research associate at the Leibniz Institute for Food Systems Biology at the Technical University of Munich.
The manufacturing concern is how readily flour with different characteristics can be accommodated within an established process. Depending on the product, that could involve reviewing water addition, mixing conditions or formulation, then checking whether the changes preserve quality without slowing production or adding costs.
An adjustment that works in a trial also needs to remain dependable across routine production. A manufacturer supplying an established bread range has to consider whether the resulting loaves continue to meet customer expectations for appearance, texture and eating quality.
The experiment covered one location and one growing season, with one elevated-CO₂ ring and one control ring, so further independent trials are needed to establish how widely the findings apply. It didn’t quantify factory costs, but the observed reduction in baking performance gives the industry a reason to investigate how future wheat varieties will behave in commercial applications.
How much variation can millers and bakers absorb?
Millers select and blend wheat to turn a variable agricultural raw material into flour with dependable characteristics, making their ability to manage changes an important part of the bakery’s supply arrangements.
If wheat composition changes, manufacturers need to understand how suppliers will identify the difference, manage available grain and verify that flour continues to perform. An agreed specification provides a foundation, while application testing establishes what the ingredient delivers in the intended product.
Bread manufacturers seeking dough strength and loaf volume have different priorities from biscuit producers controlling spread, texture and bite. Those requirements need to inform how wheat is assessed, rather than assuming that a variety suitable for one application will work equally well in another.
Production records can strengthen discussions between a bakery and its miller by showing which deliveries require intervention, what operators adjust and whether similar problems recur. That information helps establish where consistency is being lost and what it takes to restore it.
It can also reveal whether a purchasing saving survives contact with production. A lower flour price needs to be considered alongside repeated trials, additional adjustments or rejected products where those occur.
Buying decisions should therefore consider how reliably flour performs in production alongside its price per tonne. Records of adjustments, trials and rejected products can help establish whether an apparent saving translates into lower manufacturing costs.
Manufacturers also need to know how proposed flour changes will be communicated, what testing precedes them and who investigates when production results shift. A supplier’s ability to respond becomes particularly valuable when a bakery has limited capacity for extra trials or little flexibility in its delivery commitments.
Bakers need a say in tomorrow’s wheat
The differences between varieties suggest that breeders could identify wheat that retains its baking characteristics under elevated CO₂, giving the industry an opportunity to address changes before they reach the factory.
“However, the extent of these changes depended largely on the specific wheat cultivar,” said Geisslitz.
Further trials need to establish which varieties perform reliably across locations and seasons, with manufacturers helping to define processing requirements alongside agricultural priorities such as yield and resilience.
Manufacturers also need to be specific about what they mean by ‘good quality’, since breadmaking requirements differ from those for biscuits and other wheat-based snacks. Application trials can establish whether a variety delivers the dough behaviour and finished-product characteristics each business requires.
Working with millers to assess candidate flours before they enter routine supply gives bakeries time to test production settings, consider formulation changes and establish how much variation their processes can accommodate.
Established brands have to preserve the texture and appearance customers recognise, even when a change in flour makes those characteristics harder to reproduce. Their bakers have less freedom to alter the finished loaf than a team developing a new recipe around the ingredient.
Bakers therefore need to help shape wheat development before those choices reach the mill. A variety that performs well in the field must also deliver flour they can use consistently, without repeated adjustments to keep familiar products on the shelf.
El Niño adds pressure to wheat sourcing
The 2026 El Niño presents a separate challenge through changes in rainfall and temperature, adding near-term uncertainty over wheat supplies to the longer-term questions raised by the research.
The phenomenon develops when surface waters in the central and eastern equatorial Pacific become unusually warm, altering weather patterns far beyond the ocean. In its 8 October assessment, the US Climate Prediction Center put the likelihood of strong-to-very strong conditions continuing through January–March 2027 at more than 83%.
Agricultural effects vary by region and season. Australia’s September crop report forecast wheat production of 29.9 million tonnes in 2026–27, down 17% year on year but still above the preceding 10-year average, with reduced planting largely explaining the decline.
In the UK and north-west Europe, the Met Office expects El Niño to increase the likelihood of wetter, stormier conditions during autumn and early winter, although other weather patterns will influence the outcome. Excessively wet soils could complicate fieldwork and crop establishment. British and European flour buyers are also exposed through international grain markets, where changes in overseas harvests can affect prices and sourcing options even when domestic crops escape damage.
These near-term weather and market risks are distinct from the elevated-CO₂ experiment, but manufacturers need to consider both the availability of wheat and its ability to deliver consistent baking performance.
Study:
Geisslitz S, Kaemper C, Norwig M-C, et al. Elevated CO₂ induces cultivar-dependent changes in wheat proteins linked to wheat-related disorders and baking quality, Food Chemistry, Volume 530, 2026, 151161, ISSN 0308-8146, https://doi.org/10.1016/j.foodchem.2026.151161
