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Landrace Gardening: How to Prepare Homegrown Popcorn for Popping

By Joseph Lofthouse

Tags: popcorn, Joseph Lofthouse, Utah,

For best results from homegrown popcorn the moisture should be adjusted prior to popping. This blog details the procedures I use to achieve great popping results.

popcorn molistureWhen I originally started working with popcorn I was disappointed with how poorly it popped. After doing research I realized that I needed to adjust the moisture for best popping ability. Either too little or too much water in the kernel can lead to poor popping. The difference is demonstrated by the photo of popped corn. One batch of popcorn contained 10% moisture and the other batch contained 14% moisture. The final volume was about twice as much in the batch with the proper moisture, and there were fewer old-maids.

To test the percentage of moisture in a batch of popcorn I use the following procedure:

 Grind some popcorn

 Weigh out a sample

 Dry in Oven at 250 degrees Fahrenheit for 3 hours

 Weigh again

I use a sample size of about 20 grams because that fits the capacity of my scale, and allows me to use stainless steel condiment dishes. I have also used tuna cans or pieces of aluminum foil.

I calculate the moisture content of the bulk corn using this formula:

(Original Sample Weight) – (Dried Weight)

---------------------------------------------------------- = Percent Moisture in Bulk Corn

Original Sample Weight

moisture chartA few years ago I ran a series of popping tests to determine the optimal moisture content. I made this graph which shows the final volume of popcorn compared to the percentage of moisture in each batch. I have settled on 13.5% moisture as my target. That provides a good balance between great popping ability, high quality, and good long-term storage. Too much moisture in popcorn can lead to mold.

The formula I use to figuring out how much water to add is:

Water to Add = (Weight of Bulk Seed * (1-%moisture in bulk popcorn) / (1-Target % moisture)) – Weight of Bulk Seed

Sorry if your eyes just glazed over, mine sure did when writing that. No worries, here is a real world example: the most recent that I moisturized. I had a batch of popcorn seed weighing 3000 grams. It contained 8.7% moisture. I wanted to adjust the moisture to 13.5%.

Water to add = 3000 g * (1-0.087)/(1-0.135) – 3000 = 166 grams.

Here is a photo showing what it looked like in the real world. That sure seems like a lot of water to me, but I do live in a very arid climate!!! After adding the water, I shake the bottle occasionally so that the moisture gets evenly distributed. I wait 2 days after adding water before popping the corn. Once the moisture has been measured and/or adjusted I store the popcorn in airtight containers.popcorn in a jar

I have explained the scientific method for adjusting the moisture in popcorn. It could also be done by intuition and experience: For example, storing the corn open to the air for about a week at room temperature and 70% humidity. Another example would be to arbitrarily add small amounts of water and test pop batches until it pops great. These methods are available to anyone who grows popcorn at home. This is part of the reason why I believe that landrace gardening is a path towards food security through common sense and traditional methods.

I’m feeling a bit under the weather this week, so I’m postponing the decision about a topic for next week’s post. I welcome feedback about topics that you’d like me to cover.

Joseph Lofthouse grows vegetables in a cold mountain valley where he practices the art of landrace gardening in order to feed his community more effectively.

2/2/2014 3:24:30 PM

My testing of Glass Gem corn has shown that the popping ability averages around 10%. Some cobs don't have any poppable kernels at all and others might have up to 70% that pop. There is enough diversity within the population that it could be selected for great popping ability, but it is not currently a good popping corn. Yup. The algebra made my head spin too. My poor editor! The formula is written for use in common spreadsheets. To do the math manually, first do the operations inside the (). Then do the multiplication which is signified by *. Then do the divisions which are signified by /. Then do any additions or subtractions that haven't already been done. The first thing that the formula does is calculate the weight of dry seed. That is the key to this whole process. Starting with 3000g of moist seed times 91.3% dry weight ==> 2739 grams of popcorn if all the water was removed. But we really want the percent of dry corn in the final product to be 86.5%, so we take 2739 grams and divide by 0.865 which tells us that we want the final weight of the popcorn to be 3166 grams. Since we started out with 3000 grams of popcorn then we need to add 166 g of water.

k ruby blume
12/5/2013 7:57:48 PM

Hey there I don't uderstand your formula. what does the / mark stand for in the formula? wouldnt this work 3000 x 13.5% (target moisture) - 3000 x 8.7% (current moisture = 144? I dont see how you got 166. Maybe you could explain it another way. I have some great glass gem popcorn it is not moist enough to pop well. Thanks Ruby

9/2/2013 11:57:36 PM

NebraskaDave: Great question. Popcorn with too much moisture tends to produce old maids that swell up and split instead of popping. Popcorn with too little moisture tends to produce more kernels that shatter into small fragments instead of fluffy intact popcorn, and unpopped kernels don't swell much, they just caramelize in the pan. I sometimes do the bite test to evaluate how much moisture is in the popcorn. If it is just a little flexible then it is about right. If it is hard as can be, then it is too dry. If it is soft and chewy then it is too wet. If I paid closer attention to the popcorn as it dried, I could stop the process at the right moisture and then I wouldn't need to add water later on.

8/30/2013 4:41:33 PM

Joseph, other than the scientific method, how would I know whether the lack of popping was due to not enough moisture or too much? Have a great popcorn day.