Concerned about Enzymes and the Excalibur Thermostat Control

Food Temperature vs. Air Temperature

How the Excalibur Thermostat Works

Enzyme Destruction Temperatures

Why is the Temperature on the Dial Not the Same as my Thermometer When I Test It?

In the past couple of years as the raw food lifestyle has become more popular, some raw foodists have become concerned about the thermostat in their Excalibur not holding an accurate air temperature. This concern has arisen due to a couple of reasons. One reason is the lack of instruction we have provided on how the dehydrator was designed to work, which then leads to the second reason, which is a lack of understanding on the part of the user on what is happening during the dehydration process, and how the enzymes are effected by various temperatures. Because of this concern parts of the raw food community have urged us to design a new dehydrator with a thermostat that will accurately control the air temperature.

One of our main goals as a company is to produce a product that meets the needs of our customers. Therefore we responded to the request and spent hundreds of hours testing at least a dozen different thermostats. Twice we thought we found the right one, and both times they failed to get the approval of the raw food chefs that tested them. They simply said the old one worked better. This created a concern for us because we had based our decision upon inaccurate information, for example that temperatures above 105ºF would destroy all enzymes. We then devoted our time and effort into finding the information we had to have before we could proceed with developing a new product. Based upon what we already knew from almost 30 years of experience, and information we found through recent testing and research, we have discovered that Excalibur's present design and thermostat is superior for living foods.

Excalibur Dehydrator's thermostat was never originally designed to hold an accurate air temperature, but was specifically designed for, and very accurate at controlling food temperature. However it is very important to understand what is happening in the dehydration process. Here are some aspects of the process that are most critical to understand

• FIRST, understanding the difference between air temperature and food temperature, and how the evaporation process keeps food temp cooler than air temperature

• SECOND, understanding how the thermostat works by causing the air temperature to fluctuate up and down

• THIRD, understanding at which point in the dehydration process that the enzymes are most susceptible to destruction by heat, which is while the food is in its wet state. After the food is dehydrated the enzymes can withstand much higher temperatures.

Food Temperature vs. Air Temperature

In understanding the difference between air temp and food temp it is important to know how to read Excalibur's dial.

The temperature reading on the dial refers to FOOD temperature.

In general food temperature is about 20 degrees cooler that air temperature. Therefore if you set your Excalibur at 105ºF you are setting it to hold the food temperature at around 105ºF, the air temperature may get as high as 125ºF depending upon the moisture content of the food. The reason the food temperature is cooler is because of evaporation. As the moisture on the surface of the food evaporates, it cools the food keeping it about 20ºF cooler than the air temperature. We have discovered this through hours of testing by measuring the air temperature and food temperature simultaneously during the dehydration process using a Doric Trendicator with type j thermal couples.

How Excalibur’s Thermostat Works

It is also important to know how the thermostat works. We have found through experimentation, that in order to preserve the enzymes, and reduce the risk of mold and bacteria, it is necessary to have a wide fluctuation in temperature. Because enzymes and microorganisms both thrive at the same temperature, we must be able to accomplish two things at once, keep the food temperature low enough not to harm the enzymes, and elevate the air temperature high enough to remove the moisture quickly to stop the growth of mold or bacteria. The wide fluctuation in temperature accomplishes just that.

As the air temperature rapidly rises to its high point moisture is quickly evaporated off the surface of the food. Then as the temperature lowers the dryer surface pulls moisture from the center of the food and becomes saturated again. Because of the continuous up and down fluctuation in air temperature, and constant evaporation the food temperature remains constant at a lower temperature.

After all the moisture is evaporated out of the food, the food temperature will rise and then equalize somewhere in the middle of the air temperature fluctuation. Once the food temperature rises one might get worried and think that the enzymes are dead if he or she does not understand the third critical aspect. Which is, that enzymes are only susceptible to damage by high heat when they are in the wet state, therefore once the food is dehydrated the enzymes have become dormant, and can withstand much higher temperatures.

According to our discussions with Viktoras Kulvinskas on this matter he said that we were right, and that, quote "dry enzymes can survive well up to 150ºF". He has tested food he has prepared in his Excalibur dehydrators with an experiment he created, and found it to be high in enzymatic activity. We have also done some experiments by soaking various seeds, dehydrating them at different temperatures, and soaking them again afterwards to see if they will sprout, and they did, which proves that the enzymes are alive.

Enzyme Destruction Temperatures

Something that has caused us a lot of concern, is the fact that we have heard so many conflicting opinions as to the temperature at which enzymes are destroyed. Twenty years ago Ann Wigmore spoke to our Founder Roger Orton personally and said that the food temperature had to go above 120ºF for a period of time before the enzymes were destroyed. Again in our discussions with Viktoras he said the same thing.

Ann tested different dehydrators, and found that Excalibur was the best for living foods. She found that the best technique for saving enzymes was to set Excalibur on a higher food temperature setting in the beginning and then turn it down after a few hours. However because most people may not know when to turn it down, and by leaving it on the higher setting may kill the enzymes she said to set your Excalibur on 105ºF setting throughout the entire cycle. That way the food temp will never go above 120ºF even after it is dry.

We believe this is why many have come to believe that 105ºF air temperature is the temperature at which the enzymes are destroyed, which is entirely inaccurate. We have also heard many people quote Dr. Edward Howell in his book Enzyme Nutrition that prolonged temperatures over 118ºF will destroy enzymes. We also read in his book where he says that the enzyme amylase can still convert starch to sugar at air temperatures up to 160ºF but will wear out after a half an hour. We have also read where he says that the optimum temperatures for enzymes are 45ºF to 140ºF.

Just recently we spoke with Dr. John Whitaker who is a world recognized enzymologist, and former dean of the Department of Nutrition and Food Science at U.C. Davis. He said that every enzyme is different and some are more stable at higher temperatures than others but that most enzymes will not become completely inactive until food temperatures exceed 140ºF to 158ºF in a wet state.

We appreciate you taking the time to read this information, and urge you to help us in spreading it though out the raw food community. Please contact us if you have any questions, or you know of any further information you can share with us. We want to meet the needs of the raw food community, and are still doing research in order to make any necessary changes, but from what we have been told the present Excalibur is perfect. We hope that it has helped in answering your questions regarding your Excalibur Dehydrator. Please share this with any of your friends in your community.

Sincerely,

Your Friends at Excalibur