How to Dial In Grind Size for Co-Ferment Coffee Beans
By Fellow Products | Published: 2026-10-15
Category: How-to Guides
Co-ferment beans extract faster than standard coffee. Learn a repeatable dial-in process for pour-over or espresso, with checkpoints to avoid muddy or hollow cups.
Quick answer
Start one to two clicks coarser than your usual setting for the same roast level, then adjust in small increments based on taste. Co-ferment beans often extract faster because the fruit and yeast processing adds soluble compounds, so a slightly coarser grind helps you avoid muddy or hollow flavors. Use a consistent recipe and change only one variable at a time.
Why co-ferment beans need a different starting point
Co-ferment coffees like Andrés Martinez Blackberry Co-Ferment go through a four-day anaerobic fermentation with castilla blackberries and enology yeast, followed by an open fermentation in blackberry juice. That process leaves behind extra sugars and aromatic compounds that dissolve quickly in water. As a result, the same grind setting you use for a washed coffee can over-extract co-ferment beans, pulling out dry or bitter notes that mask the fruit. Starting coarser gives you room to fine-tune without overshooting.
Set a baseline recipe before you change the grind
Pick one brew method and keep everything else fixed: dose, water temperature, brew time, and water quality. For pour-over, a 1:16 ratio (20g coffee to 320g water) at 200–205°F works well as a starting point. For espresso, use your normal dose and aim for a 1:2 ratio in 25–30 seconds. Write down the recipe so you can compare grinds fairly. If you change dose or temperature while dialing in, you will not know which variable caused the taste shift.
Adjust grind size in small, repeatable steps
Move your grinder one click coarser or finer at a time. On a Fellow Ode Brew Grinder, each click is a meaningful step, so one or two clicks is usually enough to shift extraction noticeably. For espresso, treat each click as a micro-adjustment and expect to test two or three settings before you land on the right one. Always purge a few beans through the grinder after changing the setting so you are tasting the new grind, not leftovers from the previous setting.
Taste for these three signals
Sour, thin, or sharply acidic flavors usually mean the grind is too coarse and the water is passing through too quickly. Dry, bitter, or ashy flavors mean the grind is too fine and you are over-extracting. Muddy or cloudy cups with a heavy mouthfeel can also signal too many fines, which is common when you grind co-ferment beans too fine. Aim for a cup where the blackberry note is clear and the finish is sweet, not syrupy or hollow.
Keep your grinder consistent between bags
Co-ferment beans are often roasted lighter or darker than your usual coffee, and that changes how they grind. If you switch between co-ferment and standard beans, reset your baseline instead of assuming the same setting will work. A worn or misaligned grind dial makes dialing in much harder because the numbers no longer match the actual burr gap. If your Ode Brew Grinder feels loose or the dial jumps, replacing the grind dial restores the precise adjustments you need for repeatable results.
Step-by-step dial-in process
- 1. Start one to two clicks coarser than your usual setting: Use the grind setting you normally use for a similar roast level, then move coarser by one or two clicks. This gives you a buffer against over-extraction, which is common with co-ferment beans. Checkpoint: If the first cup tastes sour or thin, you are still too coarse. If it tastes dry or bitter, you went too fine.
- 2. Brew a full cup and taste it black: Do not add milk or sugar during dial-in. Taste the coffee at a comfortable temperature and note the first flavor that hits you, the middle, and the finish. Checkpoint: A clear blackberry note with a sweet finish means you are close. A hollow or papery taste means you need to go finer.
- 3. Adjust one click finer if the cup is weak or sour: Move one click finer and brew again. Wait for the grinder to finish purging before you brew so you are tasting the new setting. Checkpoint: If the cup becomes bitter or drying, back off half a click or return to the previous setting.
- 4. Adjust one click coarser if the cup is bitter or dry: Move one click coarser and brew again. Co-ferment beans can turn bitter quickly, so a small change often makes a big difference. Checkpoint: If the bitterness fades but the cup still lacks sweetness, try a slightly lower water temperature before changing the grind again.
- 5. Lock in the setting and note the recipe: Once you get a cup with clear fruit and a sweet finish, write down the grind setting, dose, water weight, temperature, and brew time. Use that as your baseline for the rest of the bag. Checkpoint: If the coffee tastes different a few days later, adjust grind by half a click rather than changing multiple variables.
Products that support this process
- Andres Martinez, Blackberry Co-Ferment: Andrés Martinez Blackberry Co-Ferment is a limited release from Colombia, processed with a four-day anaerobic fermentation using castilla blackberries and enology yeast, then an open fermentation in blackberry juice. Roasted by Mom 'n 'em in Cincinnati. This is the kind of coffee that rewards a coarser starting grind because the fruit-forward processing adds fast-extracting compounds. Expect bright, eccentric flavors that can turn muddy if you grind too fine.
- Rebrew Stagg EKG Electric Kettle: Rebrew Stagg EKG Electric Kettle offers precise temperature control and 1200 watts for quick heat time. It is a refurbished model with the same features as the original. Consistent water temperature is critical when dialing in co-ferment beans because small temperature changes can shift extraction. A kettle that holds temperature lets you isolate grind size as the only variable.
- Ode Replacement Grind Dial: Ode Replacement Grind Dial is a direct replacement part for Ode Brew Grinders, available in Matte Black and Matte White. It ensures accurate grind size adjustments. If your grind dial is worn or slipping, your click settings become unreliable. Replacing it restores the precise adjustments you need to dial in co-ferment beans without guesswork.
