MAKING FPJ
- May 7
- 6 min read
MAKING FPJ
Korean Natural Farming (KNF) is a method of growing food that mimics Nature. It is based on
Enhancing the soil biology so that plants can obtain their own nutrition on demand using symbiotic relationships with soil biology
Cycling organic matter on site to avoid outside inputs, supply chains, waste, and runoff
Directing plant growth for maximum quality and yield using fermented inputs of plant material and other edible, non-toxic local ingredients
Fermented Plant Juice (FPJ) is a fermented input used as an agent for Biochemical Signaling Technology (BST), which directs plant growth in the KNF system. The processing method preserves the hormones, enzymes, cofactors, and other chemicals that direct plant activity.
The part of the plant and stage of development determine what biological response the signal promotes. For example, tender leaf tips direct leaf growth, underdeveloped fruit directs fruit development, and ripe fruit promotes ripening.
Fermented Plant Juice (FPJ) is prepared through a series of steps designed to extract, preserve, and stabilize plant biochemical signals for storage and use. Each step serves a specific purpose in the fermentation cycle.
Note: While FPJ and other KNF inputs contain low levels of nutrients, their purpose is not fertilization, but rather biochemical signals to direct plant growth. Plants in a KNF system obtain nutrients from the soil on demand with the symbiotic relationship with soil biology (using IMO, Indigenous Micro-Organisms).
FERMENTED PLANT JUICE (FPJ) METHODOLOGY AND PROCESSING STEPS
1. Collect the Correct Plant Material
Successful FPJ begins with proper collection. The material selected determines the biochemical signals present in the final serum.
Consider:
Type of plant
Plant part
Growth stage
Time of day
Weather conditions
Plant material is typically collected before sunrise, when plant energy is concentrated in the sap and before photosynthesis begins.
For FPJ to signal vegetative growth, it is mandatory to harvest tender leaf tips before sunrise, prior to photosynthesis, because the plant’s biochemistry shifts from active growth (which signals vegetative growth) into energy collection and sugar production (which does not).
2. Prepare the Plant Material
The plant material is prepared by cutting, bruising, or rubbing it with dry raw sugar.
The sugar creates osmotic pressure, drawing fluids from the plant cells while simultaneously initiating fermentation through naturally occurring wild surface yeast.
Plant material should be small enough for sugar to extract plant juices. Siphoning action results from the sugar’s osmotic pressure.
The material should not be so small that organic matter settles to the bottom, as this can lead to rot.
The size and processing depend on the type of plant material, but the general rule of thumb is to keep sizes no smaller than a thumb. Fruit can be cut. Some leaves will have to be rubbed gently with sugar.
3. Layer with Dry Raw Sugar
Place the plant material into a fermentation vessel and layer it with raw sugar, using more sugar on the top levels than the bottom. Use roughly equal parts sugar by weight for the entire process, including final stabilization.
Leave one-third airspace in the container and cover it securely with a breathable lid, such as cloth. The ferment needs oxygen, especially at the beginning, for yeast to form colonies, and it needs to be able to off-gas. This wild ferment is an aerobic process.
During this stage:
Plant fluids are extracted
Wild aerobic fermentation begins
The liquid starts bubbling as yeast metabolizes plant sugars
Fermentation typically lasts 3–5 days and should not exceed 7 days.
4. Decant the Serum
Once fermentation is complete, separate the liquid serum from the plant material. This liquid is the FPJ.
At this stage, the serum still contains:
Fine plant particles
Active microbes
Sediment and suspended solids
The remaining plant material can be repurposed, composted, or fed to animals.
5. Allow Fermentation to Finish and Sediment to Settle
After decanting, allow the FPJ to sit undisturbed at room temperature and away from light. If capped, keep it loose so that CO2 can off-gas.
During this clearing phase:
Sediment settles to the bottom
Microbial flocculates collect as bio-sludge (lees)
Fermentation finishes naturally
The serum should gradually become translucent and smell like a concentrated version of the original plant.
The sludge contains concentrated recycling enzymes and decomposition factors, and must be removed to retain the captured biochemistry. This is done through racking.
6. Rack the FPJ
Carefully siphon or pour the clear serum into a clean container, leaving the sediment behind.
This step is critical for long-term stability and, more importantly, efficacy.
If the sludge remains in the FPJ:
Putrefaction may begin
Valuable biochemical signals can break down
Biofilms may form
Spray equipment may clog
A properly racked FPJ is cleaner, more stable, and better suited for biochemical signaling.
7. Stabilize with Sugar
If the FPJ remains biologically active after settling, add additional raw sugar until saturation is reached. Mix until some crystals no longer dissolve. This lowers water activity and forces the biology into dormancy, preserving the biochemical signals in stasis until diluted for use.
If enough sugar was used during fermentation, especially with fruits, additional sugar may not be necessary. If the FPJ does not go dormant after saturating with sugar, see the troubleshooting section below.
8. Cap and Store Properly
Once the FPJ is fully settled, stable, and no longer producing gas or sediment, tightly cap the container and store it away from heat and light.
Unlike during fermentation, oxygen is no longer beneficial. Exposure to oxygen can degrade delicate signaling molecules and encourage vinegar formation by Acetobacter carried by vinegar flies.
Before sealing:
Ensure no bubbling or gas production remains
Confirm that the smell and taste are pleasant and plant-like
Avoid sealing active fermentation to prevent pressure buildup
QUALITY CONTROL
Healthy FPJ should:
Be clear or translucent
Smell and taste bright, clean, and like the plant material collected
Have no sediment
Remain still at the surface; no bubbles or foam
Signs of anaerobic rot include:
Persistent cloudiness
Swampy, rotten, or sulfur smells
Surface films
Rising or fluffy sediment
If the smell shifts away from the original plant profile, the biochemical signals are being lost.
The best FPJ smells like something you would want to consume. Watching, smelling, and cautiously tasting your FPJ over time is part of learning the process.
Every FPJ should be edible. If it tastes or smells like something that is not edible, it should not be used.
TROUBLESHOOTING & QUALITY CONTROL
DURING FERMENTATION
Sugar Crystals During Fermentation
If you have undissolved sugar in your ferment, it means your ferment has too much sugar. There should be no sugar crystals at the bottom, and the sugar cap should dissolve within about a day.
Use less sugar. The 1:1 by weight is a guideline and includes any you may use to saturate when finished. The sugar cap should be a slight sprinkle and is there to prevent mold from forming on the surface. If you have proper 1/3 airspace, you are unlikely to get any mold forming. Plant material with high sugar levels, such as fruit, needs less sugar.
No Bubbles During Fermentation
No bubbles typically indicate no fermentation. Fermentation is when yeast consumes sugar and produces CO2 gas (bubbles). You may need to add a little sugar.
If you are using store-bought produce, try again. They are cleaned and sanitized. No wild yeast remains. They are also typically treated to prevent contamination growth and, therefore, are unlikely to ferment. If it is fermenting anyway, it is contamination from the store, shipping, and handling. Use only untreated plant material, ideally from your land.
Too Much or Too Little Air
If you add too much material, or if the fermentation is particularly vigorous, it may bubble over. Remove some of the plant material to stop overflowing and ensure 1/3 airspace.
Plant material tends to settle as sugar and yeast start the fermentation process. It is hard to know without experience how much volume will settle for each plant type. Since you cannot add more plant material to a ferment that has already started, fill your vessel over the 1/3 mark, but be sure to adjust it to 1/3 airspace within 24 hours.
If you are developing mold, it is most likely because of excess air space. More than 1/3 airspace leads to oxidation damage and mold. You cannot add more material, so transfer to a smaller jar or fermenting vessel. Next time, start with more material.
DECANTED FPJ
If your FPJ won’t stay saturated and activates when adding sugar rather than going dormant, you likely have an osmophilic yeast. If this happens, stop feeding it sugar.
Rack it into a clean bottle to remove any sediment, then keep an eye on it. Wait (it can take 2 or more weeks) until it goes completely dormant on its own. That means no bubbles and no new sediment. Smell and taste will tell you the quality.
Follow the quality control items in the chart. If it is healthy, with no signs of rot, cap it tightly to prevent oxidation and contamination, and store it away from heat and light.
QUALITY CONTROL
Feature | Healthy | Anaerobic/Rot |
Visual Clarity | The serum becomes translucent; you can see light through the liquid. | The liquid stays cloudy, even after several days. |
Surface | Clean and still. May have a few thin, fine particles. | A thick, white film (kahm yeast) or bubbles that don't pop. |
Smell | Bright, sharp, and smells like a concentrated version of the plant. | Swampy, cheesy, or a sulfur (rotten egg) smell. May be strong or mild. |
Sediment | Compact, distinct layer at the bottom with a sharp line. | Fluffy, lofty sediment that seems to be rising or swirling. |
Be sure to test your FPJ quality using smell and taste, following the chart above. Always smell before tasting, and do not taste if the smell is off.
If your quality control fails, dump it and try again.
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