Research & Insights
Brewer's Yeast in Kibble: In the Mix or on the Coat? A Formulator's Guide
Published
In short: whole-cell dried brewer's yeast belongs in the kibble mix, added with the dry ingredients before extrusion at 1–3% of the recipe, where it supplies protein, B vitamins and a savoury base. Yeast extracts and hydrolysed yeast belong on the coat, applied with fat after drying at 0.3–1%. Published trials have used dried yeast at 10–30% of extruded dog and cat diets without changes in digestibility.
This guide is for formulators, R&D teams, co-manufacturers and ingredient importers working on dog and cat kibble in the US, EU, UK and Australia. It covers where each yeast product enters the process, what the research reports, what brewer's yeast contributes to a recipe, how to run a bench trial and what to put in the purchase specification.
Where can yeast enter a kibble line?
Most kibble is made the same way. Dry ingredients are ground and blended, conditioned with steam and water, extruded, dried and cooled. Fat and palatants are then applied to the surface in a coating drum. That gives two entry points for a yeast ingredient:
- In the mix: blended with the other dry ingredients, so it becomes part of every kibble and counts toward the recipe's protein and nutrient budget.
- On the coat: sprayed or dusted with the fat after drying, so it sits on the surface where a dog or cat smells and tastes it first.
Why does whole-cell brewer's yeast usually go in the mix?
Whole-cell dried brewer's yeast is a protein ingredient bought at percent levels, so it belongs with the other dry ingredients. Drum-dried brewer's yeast arrives already heat-treated and inactive, which means extrusion does not change what the formulator bought it for.
Its flavour chemistry suits the mix as well. Brewer's yeast carries glutamic acid and the nucleotides IMP and GMP, the compounds behind savoury, umami taste. Because drum-dried yeast is already heat-treated, standard extrusion leaves that savoury base in place, and the trial data below confirm acceptance after extrusion.
The clearest controlled data comes from Davenport and colleagues at ADM Animal Nutrition, published in Translational Animal Science in 2023. They added dried yeast at 10% of extruded dog and cat diets, in place of pork meal and wheat middlings. Dogs chose the yeast diet first more often over two days (P = 0.005), and cats ate more than twice as much of the yeast diet as of the control (P = 0.001). Nutrient digestibility and stool quality did not differ between diets in either species. Our palatability guide covers the two-bowl results in more detail.
What does the research show for yeast in extruded pet food?
Four studies give formulators a working evidence base. Each put dried yeast or a yeast component into the dry mix before extrusion, and each reports outcomes a pet food brand cares about: acceptance, digestibility, stool quality or what survives processing.
| Study | Species and format | Yeast in the diet | What the authors reported |
|---|---|---|---|
| Davenport et al., Translational Animal Science, 2023 | Adult dogs and cats, extruded kibble | 10% dried yeast, in the mix | Dogs chose the yeast diet first (P = 0.005); cats ate 2.09 times more of it (P = 0.001); digestibility and stool quality unchanged |
| ADM Animal Nutrition technical bulletin, 2024 | Dogs, vegan extruded diet | 19% dried yeast | Over 98% of the food offered was consumed |
| Reilly et al., Frontiers in Veterinary Science, 2021 | Adult dogs, extruded diet | 29.9% dried yeast as the main protein source | Apparent total tract digestibility above 80% |
| Kilburn-Kappeler et al., Frontiers in Animal Science, 2023 | Dogs, extruded kibble | Yeast β-glucan blend | More than 100% recovery of β-glucan after extrusion; kibble characteristics, stool quality and digestibility unchanged |
What does brewer's yeast add to a recipe at 1, 2 and 3%?
Formulators budget an ingredient by what it delivers per kilogram of finished recipe. The table uses TBESBY's published specification for protein and amino acids and our September 2026 independent laboratory analysis for B vitamins. Values are typical, on an as-received basis, before processing.
| Nutrient (TBESBY typical value) | At 1% inclusion | At 2% inclusion | At 3% inclusion |
|---|---|---|---|
| Crude protein (40–46%) | +0.40–0.46 percentage points | +0.80–0.92 percentage points | +1.20–1.38 percentage points |
| Lysine (30.5 g/kg) | 0.31 g/kg | 0.61 g/kg | 0.92 g/kg |
| Glutamic acid (56.0 g/kg) | 0.56 g/kg | 1.12 g/kg | 1.68 g/kg |
| Thiamin, vitamin B1 (49 mg/kg) | 0.49 mg/kg | 0.98 mg/kg | 1.47 mg/kg |
| Riboflavin, vitamin B2 (19 mg/kg) | 0.19 mg/kg | 0.38 mg/kg | 0.57 mg/kg |
| Niacin, vitamin B3 (132 mg/kg) | 1.32 mg/kg | 2.64 mg/kg | 3.96 mg/kg |
Treat the B-vitamin figures as a natural contribution that sits alongside the vitamin premix, and confirm the finished kibble against your own analysis for any nutrient you declare.
What goes on the coat?
Coating palatants work at the surface, so they are built from the soluble flavour fraction of yeast and applied with the fat after drying. Most kibble makers source them from their palatant supplier as part of the coating system, and the level is set by that system. Whole-cell brewer's yeast does its work inside the kibble. Our guide to brewer's yeast vs yeast extract explains how the two products differ.
| In the mix | On the coat | |
|---|---|---|
| Yeast product | Whole-cell dried brewer's yeast | Yeast extract, hydrolysed yeast |
| When it is added | With dry ingredients, before extrusion | With fat, after drying |
| Typical level | 1–3% of the recipe; 10–30% in published dog and cat trials | 0.3–1% of the kibble |
| Main job | Protein, B vitamins, savoury base | Aroma and first-bite appeal |
| US ingredient name | Brewers dried yeast | Yeast extract or hydrolyzed yeast |
Can one recipe use both?
Yes, and many do. The two products do different jobs, so they do not compete for the same line in the formula. Brewer's yeast in the mix carries part of the protein and builds a savoury note through the whole kibble; an extract-based palatant on the coat delivers the first impression in the bowl. A formulator who adds brewer's yeast to the mix can review the coating level in the same trial rather than running two separate projects.
How much brewer's yeast should go in the mix?
For flavour and B vitamins, 1 to 3% of the recipe is a common working range in dry dog and cat food. When yeast also carries protein, published diets have used 10% in complete kibble and up to 29.9% as the main protein source, which is why plant-based brands use it at higher levels (see our guide to brewer's yeast in vegan pet food). A practical first bench trial is 2% in the mix against your current recipe. Species detail is in our guides to brewer's yeast in dog food and brewer's yeast in cat food.
How do you run a kibble bench trial with brewer's yeast?
- Build two diets that differ only by the yeast: add brewer's yeast at 2% and remove protein from another ingredient so both diets match on crude protein and energy, as Davenport et al. did with pork meal and wheat middlings.
- Run both through the same extrusion settings and the same fat and palatant coating, so the yeast is the only variable.
- Check kibble physicals before feeding: bulk density, expansion, hardness and colour against your production standard.
- Run a two-bowl test over at least two days. Davenport et al. offered dogs 400 g and cats 65 g of each diet once daily and recorded total intake and first choice; report the intake ratio, not only the winner.
- Send the finished kibble to your laboratory for the nutrients you declare, and keep the trial report with the supplier's specification and certificate of analysis for your QA file.
How is brewer's yeast named on a kibble label?
In the US, whole-cell brewer's yeast is declared as brewers dried yeast, the AAFCO-defined name for dried, non-fermentative, non-extracted Saccharomyces yeast from brewing with at least 35% crude protein. In the EU and UK it is the feed material "Yeasts [brewers' yeast]", entry 12.1.5 of the Catalogue of feed materials, which requires the yeast to be inactivated. Yeast extracts on the coat are declared under their own names. Our feed regulations guide covers the definitions in full.
What should a kibble maker put in the specification?
- Product identity: inactivated dried brewer's yeast, Saccharomyces cerevisiae, stated on the specification.
- Guaranteed values: crude protein, moisture, ash, fat and fibre, with the test method for each.
- Particle size: a fine, uniform powder blends evenly with ground dry ingredients; agree a sieve reference if your mixer is sensitive to it.
- Label name for each market: brewers dried yeast in the US, yeasts [brewers' yeast] 12.1.5 in the EU and UK.
- Safety limits and documents: see our safety specs guide for the Salmonella, mycotoxin and heavy metal limits pet food buyers usually ask about.
Where does TBESBY fit?
TBESBY is whole-cell dried brewer's yeast for the mix: inactivated and drum-dried at our own facilities in Vietnam from fresh brewer's yeast from leading international breweries in Vietnam, with 40–46% crude protein, moisture below 10% and ash below 6%, milled and sifted to a uniform powder. It ships in 25 kg bags or 600–1,200 kg jumbo bags with a 12-month shelf life, from a U.S. FDA registered facility. See the full specification, or request a free 1–2 kg sample for your next kibble trial.
Frequently asked questions
Should brewer's yeast be added before or after extrusion?
Whole-cell dried brewer's yeast is usually added before extrusion, with the other dry ingredients, because it is used at percent levels for protein, B vitamins and flavour. Yeast extracts and hydrolysed yeast are the products normally applied after drying, in the coating.
How much brewer's yeast goes into dry dog or cat food?
1 to 3% of the recipe is a common range for flavour and B vitamins. Published extruded diets have used 10% in complete dog and cat kibble and up to 29.9% as the main protein source in dog food. Start with a 2% bench trial and a two-bowl test.
Does extrusion change brewer's yeast?
Dried brewer's yeast is already heat-treated and inactive before it reaches the extruder. In a published study of extruded dog and cat diets with 10% dried yeast, nutrient digestibility and stool quality matched the control diets.
How much protein does 2% brewer's yeast add to kibble?
At TBESBY's specification of 40–46% crude protein, a 2% inclusion adds 0.80–0.92 percentage points of crude protein to the recipe, along with about 0.6 g/kg of lysine and close to 1 mg/kg of naturally occurring thiamin.
What is brewer's yeast called on a pet food label?
Brewers dried yeast in the US, following the AAFCO definition, and yeasts [brewers' yeast], feed material 12.1.5, in the EU and UK. Yeast extracts used on the coat are declared under their own names.
Sources
ADM Animal Nutrition (2024). Technical bulletin: dried yeast in a vegan dog food.
Commission Regulation (EU) No 68/2013 on the Catalogue of feed materials, entry 12.1.5.