How to Brew Your Own 60L EM-1 Mix This Autumn
As the UK moves into the cooler, wetter days of October, it’s the perfect time to get your Effective Microorganisms (EM-A) brew going. Whether you’re making bokashi, improving compost, or feeding soil microbes before winter, brewing your own EM-A gives you a fresh, active culture ready for use across your garden, farm, or compost system.
Here’s your step-by-step guide to making a 60L brew at home — ideal for smallholdings, gardens, or community compost setups.
🧪 Ingredients (1:1:18 ratio for 60L batch)
Water (non-chlorinated): 54L (warmed to 25–27°C)
🔸 Tip: If using tap water, leave it to stand for 24 hours or aerate it to remove chlorine before use.
⚙️ Equipment Checklist
Heater (32°C max is fine for autumn brewing)
Long stir paddle
Thermometer
pH meter or strips (range 2.5–7)
Airlock
🍶 Brewing Steps
Clean & Prep
Rinse the fermenter and tools with hot water — avoid bleach or antibacterial soaps that could harm your microbes.Dechlorinate & Warm Water
Warm the water to 25–27°C, ideal for autumn conditions.Dissolve Molasses
Mix 3L molasses with ~10L warm water until smooth. This helps it blend easily and prevents sticking.Combine & Mix
Pour the molasses solution into your fermenter. Add the rest of the warm water, then 3L EM-1. Stir gently to combine without splashing.Seal & Maintain Temperature
Fit the lid tightly and attach the airlock. Keep the fermenter somewhere warm and dark (around 25–32°C).Your heater’s 32°C limit is perfect — fermentation may just take a few days longer in cooler weather.
Ferment (Anaerobic Process)
Let it brew for 7–14 days.
Avoid opening the lid too often — this is an oxygen-free fermentation.
👃 Daily Quick Checks
Spend 15 seconds each day checking:
Gas: Slight pressure or swelling = good sign.
Smell: Should be sweet-sour or “apple-cider-like”. Avoid sharp, rotten, or solvent odours.
Temperature: Stay near your target of 25–30°C.
💡 Already using EM-A? Try Actiferm — it’s pre-brewed and ready to activate soil life instantly.
✅ When It’s Ready (Day 6 Onward)
pH: Ideal range 3.2–3.6 (anything below 3.8 works).
Smell: Pleasantly sour and slightly sweet.
Visuals: Bubbles or a thin white film (kahm yeast) are normal — stir back in gently.
Green or black mould? Discard and start fresh.
🧴 Finishing & Storage
Once the brew passes the smell and pH tests:
Decant into airtight bottles, filled to the brim.
Store cool and dark (shed or cupboard).
Shelf life: 90 days unopened, 60 days after opening.
⚠️ Troubleshooting Tips
pH still above 3.8 after 10–12 days?
Add 1–2% more EM-1, stir gently, and re-seal.Bad smell?
Likely oxygen contamination — sanitize and start again.Foam or white film?
Totally normal. Keep it sealed and anaerobic.
🌿 Why Brew EM-A in Autumn?
October’s mild temperatures and lower light make it ideal for brewing microbial inoculants before winter. By having a batch ready, you can:
Kickstart compost piles before the cold slows them down
Spray soils and leaves to build resilience
Ferment bokashi waste efficiently indoors
Brewing your own EM-A now means your microbes are active and ready for spring planting.
The EM Activator enhances the activation process of the base solution (EM-1®) with A+ Sugar Cane Molasses, creating EM-A, also known as Actiferm. The fermenting vessel includes a heating element, pressure release valve and all the taps you will need. As the microbes within EM-1 are facultative, no bubbling is required.
For optimal results, get the water up to temperature before adding EM-1 and never use mains water. Mains water contains chlorine which will kills the microbes. Rain water, spring or borehole water is great. If you do not have access to that then you can de-chlorinate water by letting the chlorine evaporate for a period of time.
