Some people with alpha-gal syndrome report concerns or reactions related to certain yeast products, as manufacturing processes or added ingredients may sometimes involve mammal-derived components that are not always obvious from the label. Because ingredient sourcing and processing methods can vary between brands, it can be helpful to contact the manufacturer directly to ask about carriers, growth media, anti-caking agents, or any animal-derived processing aids. When in doubt, choosing brands that clearly disclose allergen and ingredient sourcing information can make baking decisions easier.
Having written to several companies that sell baking yeast, I am providing the information that I received in April 2026. This is not a guarantee of safety. I recommend contacting the manufacturer of whatever brand yeast you choose to use.
Please feel free to copy and use this letter:
Dear (Company) Customer Support,
Thank you for taking the time to review my question regarding your baking yeast products.
I would like to ask specifically about sorbitan monostearate, which I understand may be used in some yeast products as a processing aid or ingredient to assist with drying and rehydration of the yeast. Publicly available sources describe sorbitan monostearate as an ester made from sorbitol and stearic acid, but the stearic acid source may vary depending on supplier or manufacturing process. (Organic Materials Review Institute)
Because I have Alpha-Gal Syndrome (AGS) and must avoid mammal-derived ingredients, I wanted to ask:
- Is the sorbitan monostearate used in your yeast products sourced from vegetable materials, animal materials, or a combination of sources?
- If supplier sources vary, are you able to confirm whether current production uses only non-mammalian sources?
- Are there any (company name) yeast products that do not contain sorbitan monostearate?
- Do you have any guidance for customers with Alpha-Gal Syndrome who need to avoid mammal-derived ingredients?
I understand proprietary sourcing details may be limited and suppliers can change over time, but any clarification you can provide would be greatly appreciated.
Thank you for your time and assistance.
Sincerely,
The responses I received in April 2026 are below. Please read the full disclaimer for this website.
Disclaimer Summary: Alpha-gal Digest is not responsible for the safety of ingredients for each individual. Manufacturers may change ingredients and processing methods at any time without notice. Always verify the safety of all products and ingredients for your specific needs.
Disclosure: Some links may be affiliate links. If you make a purchase through them, I may earn a small commission at no additional cost to you. Thank you for supporting my channel!
Bob’s Red Mill

Contact: [email protected]
Email Response (4/28/26):
“Thank you for contacting Bob’s Red Mill!
Our Active Dry Yeast is vegan and source of the sodium monostearate is plant-based. No mammal/animal products are used.”
Fleishmann’s Yeast

Contact: [email protected]
- Is the sorbitan monostearate used in your yeast products sourced from vegetable materials, animal materials, or a combination of sources?
- If supplier sources vary, are you able to confirm whether current production uses only non-mammalian sources?
Email Response (4/28/26):
AB Mauri for Fleishmann’s Yeast: “1&2. Our sorbitan monostearate sources used in yeasts made in the US and Canada are classified as vegetarian- I am currently unable to confirm the status of the sorbitan monostearate for our yeasts originating in Mexico, but can provide an answer as soon as I receive confirmation from our supplier.”
3. Are there any (company name) yeast products that do not contain sorbitan monostearate?
Response:
“We do carry several types of yeasts that do not contain sorbitan monostearate, such as our items 2116, 2020, 2127, etc.”
King Arthur Baking

Contact: [email protected]
Email Response (4/28/26):
“We sell three types of yeast on our site:
SAF Red Instant yeast: Sorbitan Monostearate is derived from vegetable products (corn) and is added to prevent clumping. According to the manufacturer, this yeast is Halal, Vegan, Non-GMO, and Kosher (Kosher symbol on bottom of bag). Please see the manufacturer’s website (www.lesaffrebaking.com) for certification details.
SAF Gold Instant Yeast: Sorbitan Monostearate is derived from vegetable products (corn) and is added to prevent clumping. According to the manufacturer, this yeast is Halal, Vegan, Non-GMO, and Kosher (Kosher symbol on bottom of bag). Please see the manufacturer’s website (www.lesaffrebaking.com) for certification details.
Red Star Active dry yeast: Sorbitan Monostearate is derived from vegetable products (corn) and is added to prevent clumping. According to the manufacturer, this yeast is Halal, Vegan, Non-GMO, and Kosher (Kosher symbol on bottom of bag). Please see the manufacturer’s website (www.lesaffrebaking.com) for certification details.”
Red Star Yeast

Contact: https://redstaryeast.com/contact-us/
Email Response (4/28/26):
- Is the sorbitan monostearate used in your yeast products sourced from vegetable materials, animal materials, or a combination of sources?
Response:
“The sorbitan monostearate we use is sourced from vegetable materials only.”
2. If supplier sources vary, are you able to confirm whether current production uses only non-mammalian sources?
Response:
“We confirm we only use non-mammalian/non-animal sources.”
3. Are there any (company name) yeast products that do not contain sorbitan monostearate?
Response:
“Yes, The Red Star All-Natural Active Dry Yeast in the small packets, three-to-a strip and Red Star Fresh Cake Yeast, 2 oz are the only products that we produce that do not contain the sorbitan monostearate.”
