Here is The Freeze Dried Candy Network’s guide to FTM on a Harvest Right freeze dryer and it is used for the process of making freeze dried candy in a fraction of the time compared to what it takes in standard mode – but without the hassle and uncertainty of upgrading to “Candy Mode”.

This would be considered an advanced technique because we are essentially operating the machine manually without the assistance of the automated software.

In an attempt to make this guide as simple as possible to follow, I will list the steps that must be followed in the EXACT order. I will then list them with an explanation for each step and it is highly recommended that you read the entire guide with the explanations.

DISCLAIMER:

This is an advanced technique that can RUIN your equipment if you do not have a firm grasp on what it is you are doing. Please take the time to understand the mechanics and the science involved with this write-up. As stated in the disclaimer, I will not be held responsible for any outcome you, anyone else or your/their equipment/possessions experience as a result of reading and acting upon this write-up. Furthermore, this write-up and the methods laid out here are NOT endorsed by Harvest Right and may void your warranty. Always follow the instruction manual that was written by Harvest Right for your freeze dryer. This write-up is for informational, educational and entertainment purposes only.

Functional Testing Mode (FTM) Instructions

1. Load up your trays and set them close by

2. Close and latch the door as well as the drain valve

3. Turn on the machine

4. Press the leaf icon on display screen

5. Turn on the heat function

6. Let the heat reach ~140*

7. *TURN ON THE FREEZE FUNCTION (IMPORTANT)*

8. *Let the chamber freeze at least 11 minutes (IMPORTANT)*

9. Open the door and load trays into the heating rack

10. Close the door, turn the handle and make sure it will seal

11. Turn on the vacuum function

12. Wait, listen and watch to make sure the vacuum is working.

1. Load up your trays and set them close by

The reason we load the trays and set them close to the machine is so that we put them in at nearly the same time. Why? Because candy doesn’t need to be heated for too long before it starts to become soft.

As soon as we load a tray, heat from the heating rack begins to transfer to the contents of the tray. Imagine loading a tray then leaving it on the heated rack for 5 minutes while you place product on the next tray to be loaded.

By the time you load your last tray, the first ones in will have already warmed significantly. Things will turn to goo if they are too soft. We don’t want this to happen because we want a nice consistent product.

Best to stage your trays (grab these stackers if you haven’t already) (#ad) stacked nice and neat close by.

2. Close and latch the door as well as the drain valve

This is self explanatory for the most part, but it is always worth noting to visually inspect your machine before operating it.

Close the drain valve and shake any moisture from the discharge tube that might be there from the previous batch. Now check your rubber door gasket to ensure it is clean and free of debris that might keep the acrylic door from creating a seal against the gasket.

If any dust or debris is present, wipe it with a lint-free cloth and a 50/50 isopropyl alcohol and water solution applied with a spray bottle. Make sure the gasket is dry before closing and latching the door. Turn the latch to the right, sealing the door.

3. Turn the machine on

Reach back around the machine to the right and flip on the main power switch. The display screen will light up. At this point, double check to make sure your vacuum pump is plugged into the back of the freeze dryer. We will be operating the pump with the controls on the freeze dryer.

4. Press the leaf icon on the display screen

The leaf icon is in the upper lefthand corner of the display screen (most Harvest Right models). Pressing the leaf icon takes us to the Functional Testing Menu.

This is where the magic happens. All of the freeze dryer’s main functions can be accessed here. If you recall, the Harvest Right manual has users run through some basic functional tests. This is where that happens.

This is also where we get to have control over the functions (except for heat, you will notice that the heat fluctuates in the next step).

5. Turn on the heat function

First function to be turned on is the heat. Note that the heat will NOT stay consistent during this entire process. The tray rack will heat and cool between ~130* and ~160* this is normal. However, we are looking for a certain temperature.

Important side note: Sometimes people will pre-heat candies in order to soften them. We will mention more about this in another step to follow.

6. Let the heat reach ~140*

Let the tray rack heat up to ~140*. This ensures that the tray rack is nice and warm before we turn on the freeze.

Note that some people turn on the heat and the freeze at the same time and while there is nothing wrong with that, the advantage we gain by turning on the heat before the freeze is that the heat is not fighting the freeze cycle and may reach the 140* mark a little faster.

This first function is the 2nd most important of the functions because the candy needs to be heated in order to expand.

7. TURN ON THE FREEZE FUNCTION (IMPORTANT!)

STOP. Go back to the beginning of that header and read it again. TURN ON THE FREEZE – and that is the most vital function of the entire process, especially when working in FTM to process candy.

There is no need to sublimate moisture from the candy since most candy only has a moisture content of about 5%. Turning on the freeze function is what saves our vacuum pump from certain death.

Without the frozen vacuum chamber the small amount of moisture in the candy would go straight into the vacuum pump and contaminate our oil before being expelled through the gas ballast.

Although this is less of a concern for oil-less vacuum pumps, it is still a necessary step. The inside of the vacuum chamber becomes a cold trap. Turn on the freeze function and listen for the condenser to kick on. It will be noisy and you can’t mistake it for anything else.

8. Let the vacuum chamber freeze at least 11 minutes (IMPORTANT)

11 minutes is about the very least amount of time we would want to wait for the cold trap to start doing its thing.

If you want to be extra sure because you live in a climate with high humidity, let the chamber freeze for 15 to 20 minutes. Turning on the freeze function and letting the chamber freeze are of the utmost importance.

We do NOT want moisture going into our vacuum pumps.

9. Open the door and load trays into the heating rack

We can finally insert our pre-loaded trays. Work efficiently though because as soon as the trays touch the tray racks, the candy will start to heat and it doesn’t take much to soften some candies up.

Pre-heating candy can be beneficial for some candies, but for the majority of the most popular ones, just putting them into the machine while you are getting things going will be fine.

Do not pause for long at this step unless you mean to. 5 minutes of heating before the vacuum is turned on doesn’t seem like a lot, but it is.

10. Close the door, turn the handle and make sure it will seal

Close your door and turn the latch to the right until door closes on the gasket nice and snug. Be sure to double check your drain valve to make sure it is closed.

This is very important so that we aren’t running the pump without resistance, which can ruin it. Also give a second look at the rubber gasket to make sure there is no debris that might prevent a good seal for the next step.

11. Turn on the vacuum function

Once the trays are in and we’ve double checked that the drain valve is closed and that the freeze function is working (you should see ice forming on the inside of the vacuum chamber), it’s time to toggle the vacuum pump button the control screen.

Be sure to touch the screen deliberately and quickly, but wait for a few seconds before pressing again because there is a delay for the pump to kick on.

Be patient, but be ready to press that button again if the pump doesn’t click on.

12. Wait, listen and watch to make sure the vacuum is working

I like to stand there in the candy room and watch the mTorr until it reaches <500 and I make sure the oil in the sight glass stays clear.

If it gets a little cloudy, I’ll let it go as long as it starts to clear up. If it gets milky looking, I stop the pump, open the valve and reevaluate everything. If oil is milky, I do an oil change and start the process over again but next time around I let the chamber freeze for 20-30 minutes before proceeding, to remove all doubt.

Milky looking oil means that there is too much moisture in the oil.

In Conclusion

This has been a rundown on how to freeze dry candy in Functional Testing Mode (FTM). This guide was written for users that have already mastered their machines but find that they need to increase output and up their candy game.