What is the ideal particle size for plant-based beverages

Particle size distribution directly governs suspension stability, mouthfeel, sedimentation rate, solubility and opacity of plant-based beverages. For dry-fractionated pulse protein concentrates (pea, fava bean, lentil) used to fortify ready-to-drink plant milk, protein shakes and powdered beverage bases, D50 and D90 are the primary control indicators. This article distinguishes two critical scenarios: dry protein powder raw material specification (after air classification) and final liquid beverage particle size after hydration/homogenization, aligned with dry fractionation technology on protein-mill.com.

1. Two Critical Measurement Scenarios

Scenario A: Dry protein concentrate powder (input raw material before liquid processing)

This is the PSD controlled during grinding and air classification on your dry fractionation line.
Target specification for beverage-grade dry fractionated plant protein:

• D50: 6–15 μm
• D90 ≤ 25 μm (primary benchmark)
• Hard upper limit: D90 should not exceed 30 μm

Why this range:

1. Particles larger than 30 μm are mostly undissociated protein–starch composites. After hydration, these large particles create gritty texture and rapidly sediment.
2. If D90 < 5 μm (over-ground): excessive fractured fine starch enters the protein fraction, lowering protein purity, increasing powder static agglomeration and raising viscosity in finished drinks.
3. Narrow PSD is preferred; avoid wide distribution with coarse tailings.

Practical production guideline: When targeting beverage application, tune grinding and classifier cut-point to restrict D90 below 25 μm in the fines fraction.

Scenario B: Final liquid plant-based beverage (after mixing & homogenization)

Once dry protein powder is hydrated and processed via high-pressure homogenizer, particle size becomes much finer.
Industry ideal for stable, smooth liquid plant beverages:

• D50: 0.3–1.2 μm
• D90: 1.5–8 μm
• Critical threshold: Minimize any particle fraction >10 μm. Any significant volume above 10 μm accelerates sedimentation and introduces graininess.

Homogenization breaks soft protein agglomerates formed during rehydration, but it cannot fully disintegrate rigid dry composite particles from poorly controlled dry milling. Therefore, upstream control of dry powder D90 is the foundation of beverage quality.

2. How Particle Size Impacts Beverage Performance

(1) Mouthfeel & sensory texture

• 30 μm particles: obvious gritty, sandy off-notes; unacceptable for premium plant drinks.

• 15–25 μm: mild graininess; acceptable only for budget cloudy functional drinks.
• <15 μm: smooth, creamy texture after homogenization, matching consumer expectations for plant milk and protein beverages.

(2) Physical stability (Stokes’ Law)

Sedimentation speed rises sharply with particle diameter. Larger particles settle quickly, forming sediment at the bottom of bottles during shelf life.
Restricting dry powder D90 ≤25 μm reduces the load on homogenization and stabilizer systems, lowering reliance on thickeners for clean-label formulations.

(3) Hydration & solubility

Ultra-coarse powder hydrates slowly and tends to form surface lumps (“fish eyes”). Moderately fine powder (D90 15–25 μm) achieves fast wetting without excessive viscosity build-up.

(4) Colour & opacity

Finer particles produce brighter, whiter, more uniform beverage appearance; oversized composites create dull, uneven turbidity.

3. Grade Classification for Dry Fractionated Protein for Beverages

Premium Grade (UHT shelf-stable plant milk, ready-to-drink protein drinks)

• D90: 10–20 μm
• D50: 6–12 μm
• No measurable coarse tail >30 μm
• Requirement: Strict grinding control, multi-stage air classification to remove large composite particles.

Standard Grade (powdered instant beverage mixes, frozen smoothies)

• D90: 20–25 μm
• D50: 10–15 μm
• Accept minor volume fraction <5% above 30 μm

Not suitable for beverage (feed or bakery only)

• D90 >30 μm
• High content of large protein-starch composites → grit, sedimentation risk.

4. Process Adjustments to Hit Beverage-Grade PSD in Dry Fractionation

1. Set mild grinding intensity to avoid both under-liberated large composites and over-fractured starch fines.
2. Adjust air classifier cut-point to reject particles >25 μm into middling streams for recirculation.
3. Deploy secondary polishing classification to strip coarse tailings from protein fines.
4. Monitor PSD via laser diffraction (dry dispersion mode) to track D90 continuously.
5. Maintain stable raw material moisture (8–10.5%) to prevent agglomerates that artificially inflate measured particle size.

5. Common Misconception

Smaller is not always better. Pushing dry protein D90 below 8 μm requires severe over-grinding:

• Starch granules shatter into micro-fines and contaminate protein fraction;
• Maximum achievable protein purity caps out (difficult to reach 65–70% protein);
• Powder static increases, causing handling difficulties and hydration lump formation.

For dry-fractionated plant protein powder used in plant-based beverage production, the ideal particle size target is D90 ≤25 μm, preferred range D90 = 10–20 μm and D50 = 6–15 μm. This balance delivers smooth sensory properties, good hydration behaviour and acceptable beverage stability, while avoiding the purity penalty caused by over-grinding.
After hydration and homogenization in liquid production, the final beverage targets D90 between 1.5–8 μm. Controlling the dry powder PSD upstream in air classifier mills is the most cost-effective strategy to avoid grit, sedimentation and formulation challenges in finished plant beverages.