Various FPJ Questions


Hi. I recently discovered KNF and it really resonated with me. I’ve been going through as much reading material as possible and last week I made a batch of Comfrey FPJ following the instructions in Chris Trump’s How To FPJ video.

After making my FPJ, I read in this paper that you need to stabilize your FPJ by adding equal parts by weight of brown sugar to the solution. I did this yesterday and then later saw people on this board suggest equal parts by volume, which is a very different quantity of sugar.

Today I checked on my FPJ and it looks like most of the sugar went out of solution with the FPJ:

OK, finally here are my questions:

  1. Did I add way too much sugar?
  2. If I siphon off the FPJ from the mass of sugar below will it be super saturated properly now?
  3. If I make another batch of Comfrey FPJ, would it be ok to reuse the excess sugar from this batch?
  4. After super saturating FPJ, should I adjust the application ratio to account for the additional sugar diluting the FPJ?
  5. Without super saturating, roughly how long is FPJ good for at room temperature and in the refrigerator?
  6. When making FPJ, Drake says to only use a sugar cap when fermenting fruit. However, Chris Trump adds one in his video when using Banana Flowers and says the cap is very important. When should and shouldn’t I use a sugar cap?

Thank you for everyone for helping spread the knowledge of KNF!

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Best Answer

Hi there,


  1. Yes, so here is the deal: when adding sugar you should stir the solution, at first you’ll notice how fast the sugar sinks and dissolves, when aproaching saturation the sugar will sink in “slow motion” and need more stirring to dissolve, but when you see sugar precipitating at the bottom and not dissolving, regardless of how much you stirr, then the FPJ is saturated.
  2. Most likely yes, if not i guess it will be very close to, but just add a little bit of sugar until you notice it precipitating at the bottom, then you know for sure its super saturated.
  3. You could try, in theory the microbes there wont differ but keep in mind that the sugar is no longer dry, so im not sure if it will create enough (if any) osmotic pressure to extract everything from the new plant material. Anyway, you still could use that sugar in the kitchen for example.
  4. Not sure i understood what you mean here.
  5. Outside I would say 3-7 days, depending on your specific conditions, temperature mainly. Just check that yourself, if you see bubbles in the FPJ, they are still there, when bubbles become less intense its an indicator the food is running out and the microbe population is fading. When the solution starts smelling like alcoohol then it’s already degrading, it is still usable but less effective. In the fridge at least 6 months.
  6. If you think of it, banana flower is a material with more in common with fruit than with the tender parts of plants we use in FPJ, I believe that’s why Chris does the sugar cap. So I would say sugar cap for fruit or fruit like plant materials, stuff which is denser and has more fiber in it when compared to regular tender shoots or leaves (which is what we use in FPJ).

Hope it helps!

  • solomon
    Thank you for all the helpful information! I was thinking I would use the excess sugar in my comfrey FPJ for stabilizing a new batch, not for doing the actual extraction. Do you think it would work for that purpose? Regarding question 4. I meant that, if an application of FPJ requires 1:500 dilution and I am increasing the volume of my FPJ using sugar to stabilize it, should I increase the amount of FPJ in the ratio for my application to account for the added sugar.
  • Hugo Matos
    Might work to some extent yes, but most likely you will get noticeably more volume in your FPJ after adding it, and not that much saturation, meaning you will still need to add dry sugar. Just try saturating with a little of that wet sugar and if that happens, if it really doesn’t saturate the solution all that much, but mostly adds volume to it, I would do the following: Put that sugar in a really fine strainer and let the liquid to drain for a long time, half a day or even a whole day. Let gravity do the work but be sure of one thing, that sugar is not letting the moisture to go away β€œwithout a fight”. So don’t expect to have regular sandy like sugar after it, this is still a workaround. Although, after straining, the sugar will be noticeably drier, and way more effective when saturating a liquid. (Also, don’t forget that all the strained liquid is perfectly good FPJ) Regarding question 4, you’re overthinking it, dilution ratio remains the same, whether a solution is supersaturated or kept in the fridge.
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