What enzyme is added to King Arthur flour and why?

December 8, 2025 •

3 min read

Over 90% of commercial bread flour in the U.S. contains added enzymes or other improvers to standardize baking performance. In King Arthur flour, the key enzyme added is fungal alpha-amylase, a carefully sourced ingredient that ensures consistency and dependable results for home bakers.

Quick Summary

The enzyme added to King Arthur flour is fungal alpha-amylase. This ingredient improves yeast performance, leading to better bread volume, a softer crumb texture, and enhanced crust color. It is used to ensure consistent baking outcomes for consumers.

Key Points

Fungal Alpha-Amylase: King Arthur flour contains fungal alpha-amylase, an enzyme sourced from fungi and considered vegan.
Improved Consistency: This enzyme ensures reliable flour performance by eliminating batch-to-batch variations in enzyme activity found in traditional malted barley flour.
Enhanced Yeast Activity: The enzyme breaks down starches into simple sugars, providing a food source that boosts yeast fermentation for a better rise.
Superior Baking Results: It leads to improved bread volume, a softer crumb, and a richer crust color due to enhanced caramelization.
Sustainable Production: The switch to fungal alpha-amylase was partly motivated by its more sustainable production process, which is less water and energy intensive than malting barley.
Transparent Labeling: The company lists "enzyme" on its packaging to inform consumers of the additive.

Understanding Fungal Alpha-Amylase

For many years, King Arthur Baking Company used malted barley flour to provide the necessary enzyme activity in their flours. However, in recent years, they have transitioned to using a more consistent, specific enzyme: fungal alpha-amylase. This fungal-derived enzyme is considered vegan and is used in a very small percentage to improve performance without acting as a filler. The company made this change to overcome the batch-to-batch variability that can occur with malted barley flour and to adopt a more sustainable and less water-intensive production method.

The Enzyme's Role in Baking

Fungal alpha-amylase is a catalyst that breaks down complex starch molecules into simple sugars. This process is crucial for yeast-leavened baked goods, as these simple sugars serve as food for the yeast. Without sufficient sugars, yeast activity can be sluggish, resulting in poor oven spring and texture. The controlled addition of this specific enzyme ensures that yeast have a readily available food source throughout the fermentation process. This leads to a more vigorous rise, better overall volume, and a more uniform, tender crumb.

The Importance of Consistency

Millers add enzymes to flour to correct for natural variations in wheat crops that can occur due to climate and growing conditions. By standardizing the enzyme levels, King Arthur can provide a product that performs reliably for every bake. This predictability is especially important for home bakers and commercial bakeries that need consistent results from their ingredients. This added consistency is a core reason for the company's switch from malted barley flour to the more stable fungal alpha-amylase.

Fungal Alpha-Amylase vs. Malted Barley Flour

The move from malted barley to fungal alpha-amylase reflects an evolution in baking science, prioritizing consistency and efficiency. Here is a comparison of the two approaches:


Feature	Fungal Alpha-Amylase	Malted Barley Flour
Source	Produced from fungi, such as Aspergillus oryzae.	Made from sprouted barley grains that are dried and ground.
Consistency	Highly consistent, with less batch-to-batch variation.	Can have some natural variability in enzyme efficacy depending on the crop.
Sustainability	Less water and energy intensive in its production.	Production process can be more water and energy intensive.
Enzyme Content	Provides a precise, controlled level of active enzymes.	Enzyme levels can vary slightly due to natural variations in the barley crop.

How This Enzyme Improves Your Baking

The presence of fungal alpha-amylase provides several tangible benefits for baked goods, particularly yeasted breads:

Consistent Performance: Eliminates the variables that come from using ingredients with natural fluctuations, ensuring predictable and repeatable results.
Improved Rise and Volume: By providing a reliable food source for yeast, the enzyme promotes robust fermentation, leading to a higher rise and better oven spring.
Enhanced Crust Color: More available sugars lead to increased caramelization during baking, which results in a deeper, more golden-brown crust.
Softer, More Tender Crumb: By modifying starch structure, the enzyme contributes to a softer and more uniform interior crumb texture.
Extended Shelf Life: Some amylases, including this one, help delay staling, keeping the baked product feeling fresher for longer.

What This Means for Bakers

For the average baker, the addition of fungal alpha-amylase simply means a more reliable and consistent product. For artisan and sourdough bakers, the discussion is sometimes more complex. Some believe it can affect the balance of natural fermentation, while others report no issues. The key takeaway from King Arthur's own blog is that the change was made for consistency and sustainability, and most bakers will not notice a difference. For those who prefer a flour with no additives, organic or specialty flours from other brands may be available. However, the vast majority of commercial flours in the U.S. contain some form of enzyme or dough conditioner to improve performance.

Conclusion

The enzyme added to King Arthur flour is fungal alpha-amylase. This addition is a modern milling technique designed to improve baking performance, ensuring a better rise, enhanced crumb texture, and more consistent results for bakers of all skill levels. By providing a stable food source for yeast, this vegan-friendly enzyme helps achieve the desired qualities in yeasted baked goods. For home bakers, it translates to peace of mind, knowing that every bag of King Arthur flour will deliver reliable performance, regardless of the natural variations in the wheat crop used. This small addition makes a significant difference in the final product's quality and consistency.

King Arthur Baking Company is transparent about its use of enzymes for superior flour performance.

Frequently Asked Questions

King Arthur transitioned to fungal alpha-amylase for greater consistency and sustainability. Unlike malted barley, which can vary by batch, the engineered enzyme provides a predictable level of activity, and its production is more energy and water-efficient.

Yes, fungal alpha-amylase is considered safe for human consumption and has been used in the food industry for decades. The enzyme itself is a protein catalyst that is denatured during the baking process, meaning it becomes inactive from the heat.

Some bakers have reported their sourdough starters behaving differently after switching to flour containing added enzymes, though many others report no issues. King Arthur Baking Company attributes most starter problems to other factors, such as seasonal temperature changes, and offers support for troubleshooting.

Yes, you can use King Arthur flour to feed your sourdough starter. While there have been mixed reports from bakers, many continue to use it successfully without any negative impact on their starter's health or activity.

The search results don't provide explicit information on whether the fungal alpha-amylase is genetically modified, but enzymes are often produced via fermentation using microbes. For specific information on their sourcing, consumers can contact King Arthur Baking Company directly.

Diastatic malt contains active enzymes, including amylase, that break down starch into sugars to aid fermentation. Non-diastatic malt has had its enzymes inactivated by heat and is used primarily for flavor and color.

Most commercial flours in the U.S. contain some form of added enzyme or dough conditioner to standardize performance, though levels and types can vary. Some specialty or organic brands explicitly state if no enzymes are added.

Using too much diastatic enzyme, or an excess of alpha-amylase, can break down too much starch, leading to a sticky dough that is difficult to handle and results in a gummy, wet crumb in the final baked good.