Knowledge Base

LAB Serum

LABS

Microbial culture · Soil Land Food

A living Lactobacillus culture captured from rice-wash and fed on milk — a base inoculant, part EM, that works soils, plants, and every ferment downstream.

All stagesSoil
Easy to make
7–14 days ferment
microbes, lactic-acid-bacteria, enzymes supplied
＋ Start a batch from this recipe

Ingredients

  • Rice (any type)8 oz (2 gal batch)
  • Clean non-chlorinated water (rice-wash + dilution)1 quart to capture
  • Milk with lactose (or milk powder)2 quarts
  • Molasses0.25 part per part of dilution water

How to make it

  1. Step 1

    Soak rice in clean water in an open-mouthed jar; loose lid, dark, 3–5 days until it smells slightly sour and milky.

  2. Step 2

    Decant the sour water (your Lacto culture) and throw the rice away.

  3. Step 3

    Stir the Lacto culture into milk (about 1 part culture to 2 parts milk); cover loosely and wait a few days until it curdles.

  4. Step 4

    Skim off the milk solids and keep the creamy-yellow whey — this is the Base Serum.

  5. Step 5

    Add an equal part of water to the whey to stabilise it.

  6. Step 6

    Add about ¼ quart of molasses for every quart of water you added.

  7. Step 7

    Seal tightly and store cool and shaded — it keeps for years, pH around 4.

What it is

LAB Serum (Lacto) is a base inoculant built mainly from Lactobacillus — the same fermenting bacteria behind yoghurt and sauerkraut. You capture the wild culture from soured rice-wash, feed it on milk to multiply it, keep the whey, then stabilise it with water and molasses. The result works like a farm-made EM: use it straight on soil and plants, or as the starter for SPICE, hydrolysate, and biofertilizer.

On the Nutritive Cycle: LAB Serum is an all-stages, soil backbone input. It doesn't push one growth phase — it seeds beneficial microbes that cycle nutrients, calm plant stress, and drive every downstream ferment.

When to use it

  • Soil and foliar — a general microbial boost across all stages of growth.
  • As a starter — the inoculant for SPICE compost, hydrolysate, and biofertilizer.
  • Anytime — it's the workhorse culture; keep a barrel on hand.

Materials

Base 2-gallon batch (scales cleanly to 20 gal and 250 gal / IBC):

  • Rice — 8 oz to capture the culture
  • Water — 1 quart for the rice-wash; then an equal part water to the whey
  • Milk with lactose — 2 quarts (yields ~3 quarts whey)
  • Molasses — about ¼ part (~1 pint) per part of dilution water
  • Open jar, loose lid, clean sealable barrel (50-gal drum or 260-gal IBC at scale)

How to make it

  1. Capture. Soak rice in clean water, loose lid, dark, 3–5 days until it smells slightly sour and looks milky. Decant the water, bin the rice.
  2. Feed. Stir the Lacto water into milk (~1 part culture : 2 parts milk), cover loosely, wait a few days until it curdles and solids separate.
  3. Keep the whey. Remove the milk solids; keep the creamy-yellow whey (the Base Serum).
  4. Stabilise. Add an equal part water, then about ¼ quart molasses per quart of that water.
  5. Store sealed. Lid on tight, cool and shaded.

Signs it worked / troubleshooting

  • ✅ Good: light-to-mid brown, slightly sweet-sour smell, pH ~4.
  • ⚠️ Light-brown yeast on the surface = normal, leave it be.
  • 🚫 Foul rot smell or off colours = contaminated → discard and restart.

How to store

Sealed container, cool and shaded. Stable for at least 2 years — often much longer. Keep the lid tight; unlike an active aerobic ferment, this one is done and wants to be sealed.

Related

LABSPICE Compost InoculantHydrolysateBiofertilizerIMOBokashi