Robert Roberts Limited

Print this page

Grinding

• Ground coffee is a combination of various particle size.
• A coarser grind (large particles) requires a longer dwell time for ideal extraction.
• A finer grind (smaller particles) requires less dwell time for ideal extraction.
• Water moves through the bed of coarser coffee more quickly; through a bed of finer grind more slowly.

• Match the correct particle size (grind) to brewing method and type of equipment.
• Longer Brew Times = Larger Coarser Grind
• Shorter Brew Times = Smaller Finer Grind
• Larger/Coarser Grind water moves through more quickly. Smaller/Finer Grind water moves through more slowly. Less surface area takes longer to extract materials.

Grinding increases the specific extraction surface

Optimal Brew Time Vs. Particle Size

• Adjusting the grind is the most effective way to control bitterness and astringency.
• A coarse grind will reduce contact time and decrease bitter/astringent flavour.
• A finer grind increases bitter/astringent flavours due to a dramatic increase in lactic acid, chlorogenic acid and caffeine