The Science of Home Food Preservation

Hey pioneers, welcome to episode number 307. Today, we're going to be diving into the science behind food preservation, and actually what's happening when we are preserving our food, what mechanisms are at play so that you can be safe in your home food preservation. Because there's multiple methods to preserve food at home, there's nine methods that you can use to safely preserve food at home. Now, not all methods are safe for all food types, but I find that a lot of time people don't actually understand the science behind food preservation. So at the time of this recording, we are moving right into prime gardening season and fresh produce for most of the country, and the months when a lot of us will be doing the majority of our home food preservation.

So I thought that this was a great time to be going over this so that you have a really good foundation and understanding of it, but also because I am hosting a very special live class, which is going to be teaching you how to create a food preservation plan so that you can save more food with less stress. That is going to be held on June 9th, 2021, it's completely free. To grab your seat, you're going to want to go to melissaknorris.com/harvestplan, which on a previous episode, I had the link, we didn't actually have it connected, it is now connected. So if you go to melissaknorris.com/harvestplan, it will take you right to the page where you just click the button that says, yes, reserve my seat, pop in your name and email address.

And then you will get the link on the day and the emails when we go live, and when I began teaching this class. So, highly recommend going and snagging your seat for that, I will only be teaching this particular class once this year, and it's going to be on June 9th. So make sure that you go and snag your seat for that class, but let us go back to the science behind food preservation methods. So food preservation is obviously something that humans have been doing for centuries. We now though have probably the most advanced science that explained why these different methods work, as well as in some cases, as with canning and different things like that, we have updated science that allows us to stay even safer and avoid, well quite frankly, death in some instances, but also just getting sick, and so that we can ensure we're doing it in a safe way that is going to have our food preserved for us for when we need it, but it's also not going to cause any harm to people who are eating it.

So food goes bad, because of enzyme activity and also the growth of microorganism. So when we look at the science of the food preservation, we are looking at stopping and or halting the enzyme activity that continues to break the food down. And then we're also looking at ways to stop or inhibit the growth and the overtake of microorganisms. So that's going to be bacteria, it could be fungal, you've seen mold. We also know bacteria like botulism, which is a neurotoxin, fungal growth, yeast can be something that can take over depending on specific foods, but all the basis of our home food preservation is halting those two things. Now, some methods will work by simply halting the growth of the microorganisms.

Other methods are just slowing down that activity, and some actually destroy the bad bacteria, right? So it's important to know how each form of that food preservation works and what it's actually doing. So ways that we stop bacteria growth. One, we can stop bacteria growth or microorganism growth, I should say, by removing the water. So if you remove the water, then oftentimes a lot of bacteria is not able to grow and multiply, which is why we can use salt and or dehydration in order to preserve our food. It's actually one of the factors too, a lot of people don't realize this though, even when you're freezing your food, because when we are freezing our food, it is tying up the water because it's freezing it in. And then it's in a crystal format, it's not in a liquid state anymore. And so that is actually one of the ways that freezing your food also works, and it has to do with taking away the water.

Now, as I said, salt is one of those things, dehydrating, actually just removing all of the water and freezing, but then you also have where sugar can come into play, and sugar can be a way of food preservation. Now you can't just pack food in sugar necessarily, and have it stay shelf stable, that doesn't work quite the same way as salt. But how sugar comes in to play is, especially in regards to canning, now sugar doesn't make a food safe to can or not to can, because specifically when it comes to canning, it is our acid levels, pH levels, especially in regards to botulism, which is one of the things that we need to really be paying attention to and understanding how it grows and multiplies to say safe with home food preservation, but sugar does play a role in some of our canning when we look at fruit.

So fruit, not all fruit, but most fruit is acidic. So it's definitely understanding specifically a pH of 4.6 or lower. The lower, the number, the more acidic the food is. And botulism can't grow if it's 4.6 or lower, more acidic. So knowing what pH level those fruits fall at, but most of your berries in your stone fruits are going to fall into that acidic category and they're going to be fine. But when you're making jams and jellies and syrups and that, the higher sugar content that you have in them does act as a way of preserving the food. It does help to preserve the color of the food, but it's more when the food is open and then in the refrigerator, or back in the day, they would leave open jars of jam and whatnot, would actually just sit on countertops.

But the more sugar you have, the more the sugar absorbs the extra liquid, and therefore it can't mold or grow bacteria as fast. So when I am doing low or no sugar, because we all know sugar can have health consequences, so when I am counting my jams or jellies and a lot of my fruit, I use the least amount of sugar as possible, and sometimes it's no sugar when we're talking about fruit, I'll just can it in water instead of making a syrup. But when it comes to jams and jellies, I make sure that I'm canning it in small enough jars that once the jar is opened and in the refrigerator that we're using, we're going to go through that amount before it has time to mold, because I'm not using as much sugar, I'm actually shortening the shelf life once it's opened and in the refrigerator, but it's important to know that that's the role that salt and sugar can play with water in our home food preservation methods.

So that's one of our aspects. Now we also have, as I said, acidity, so knowing those pH levels, because certain bacteria, certain fungus's, certain microorganisms can't live in acidic environments. And so it's knowing that, "Oh, if I get this to an acidic enough spot, then I'm going to be able to stop this microbial growth." Now, we also know that there's temperature. So with freezing, we are taking away the water in it's actual liquid format, but we're also lowering the temperature of the food to a temperature that the bacteria is not going to be able to multiply or grow. But as we know with freezing, yes, we can freeze raw meat and it's going to keep it in the freezer from going bad as compared to it just setting on the shelf or even in the refrigerator, the lower the temperature, but it doesn't actually kill the bacteria.

We know it just stops it from progressing, it puts it into hibernation mode, but as soon as that food comes back up to temperature, totally have to cook our raw meat, because the temperature has held it in a hibernation phase, which is keeping it preserved, but it doesn't kill the bacteria. So then we have to cook it. And that's where our heat comes in because the heat is going to kill a lot of the different microorganisms. So that's why when we look at canning specifically, and also so pasteurization, though most of us aren't using pasteurization in the form of home food preservation, we are looking at using canning as really the only true heat source we use. Dehydrating, you can go up and higher temperatures, but it's more about removing the moisture from the food, but when it comes to canning, that is why we have to pressure can foods that are not high acid.

So we have to do you use temperature. And the reason we're using a pressure can is because we can't reach a high enough temperature to kill botulism spores and other bacteria in non-acidic foods just by using boiling water, which is 212 degrees Fahrenheit. And no matter how long you boil water, it doesn't matter if you boil water for two hours or for six hours, it never gets above 212 degrees Fahrenheit, that is the temperature of boiling water. And we know from science that in order to kill botulism spores and other microorganisms, that we need the internal temperature of those jars of food to be at a higher temp under pressure, which is how you reach that, specifically 248 degrees Fahrenheit for a specific amount of time.

And that's why with your pressure canner, one, depends up on your altitude because as we know the higher, the altitude than you actually need to either increase the amount of time that it's under heat, which would be with water bath canning, you would be increasing how long you're processing of those jars. But with pressure canning, you're actually, if you're at 1001 feet or higher above sea level, then you're going to be using 15 pounds of pressure. You're adding an extra five pounds, whereas you'd be using 10 pounds for meat and vegetables. It's the total amount of time though that it's at those pounds of pressure, because once it's at that pounds of pressure, then it's specifically hitting that temperature mark. And it has to be held at that temperature for the entire time to ensure that those specific pathogens are actually killed. So we've got water activity, we've got temperature, both high and low, we've got our acidity levels. Here's where though, it can get a little bit interesting. And some of these methods use multiple of these formats, right?

And it's always better if you can have two things that are helping against the bad microorganisms that are going to make our food go bad versus one. So oftentimes you will see within freezing your food, that you need to blanch the food before freezing it. And the reason that we blanch that food before we freeze it is because the blanching is going to stop the enzyme activity, which is breaking down the food. So the enzymes aren't going to hurt us, but they are to break down the food and turn it into eventually where it's not edible. So that's why we blanch for food, especially things like winter squash, et cetera, before we freeze them, for just a couple of all of minutes, that stops that enzyme activity. So that's method number one, using heat. And then we're putting it into the freezer where it is lowering the temperature, and it's also taking away the water. So it's working three ways really, for foods that we need to blanch. And not all foods require blanching before freezing because not all of them have that continued enzyme activity that continues in them.

So there's some foods that are just fine for you to just freeze raw without doing blanching. And then there's others that it's highly recommended that you do blanch them, otherwise you're going to be very disappointed when you thought those foods and begin to cook them. That happened to me with my butternut squash when this... Oh gosh, I don't remember how many years back this was. I was just in a hurry. And I'm like, "I don't want to spend the time blanching this and then freezing it. That just seems like a waste of time." Well, yeah, rule number one, understand the science behind the home food preservation, which I now do, and I'm also sharing with you. So I froze it, peeled it, cubed it, and just froze it. And it had been in the deep freezer for, oh, I would say about probably max of three months. It hadn't really even been in the deep freezer for that long.

And took the squash out, thawed it out, roasted it, which is one of my favorite ways to have butternut squash, with a little bit of olive oil and minced garlic and some herbs, and then at the very end, just a little bit of freshly-grated Parmesan cheese, fabulous. However, it never was really, and I roasted it and cooked it, it wasn't that I hadn't cooked it long enough, it never texture-wise, no matter how long I cooked it, ever tasted done. And it had an odd flavor. Not like, "Ooh, this has gone like bad," but it just never tasted right. And it never reached the point where it felt like it was done, it still stayed hard. It was just an odd texture and flavor. And all of it was like that. And it's because I didn't blanch it beforehand, and the enzymes had been at work all the way through there.

So I learned my lesson really good, but that is an instance where a lot of the methods of home food preservation are using multiple ways in order to keep the food safe and preserved for us, be it freezer or actually on the shelf like we have with dehydration or dehydrated foods... Excuse me, canned food, et cetera. And then we use the freezer and then obviously the refrigerator, or a cool room for some of our ferments, once they have went through their initial fermentation, and then they move into the more long-term storage phase. So another thing that we have is removing the oxygen. So this is where canning definitely comes in. This is also what you will see when sometimes people are using oil. And you have to be very careful.

Let me repeat this, you have to be very careful when you are using oil to preserve food, because yes, it does create an anaerobic environment, which has also a canning jar, where anaerobic is just the removal of oxygen, the absence of oxygen. So that's the inside of a sealed canning jar. It's also food when it's underneath a liquid level and or oil level, but you still have to remember that acidity part, because botulism, I know I keep harping on botulism, but it's because it's one of the biggies, and is actual a neurotoxin and can be deadly when it comes to food preservation, so we need to understand it. And you can have botulism growth in food that's covered with oil, that's in an anaerobic environment if you don't understand the acidity pH levels that are required, what foods can be safely canned that way in which ones, not even canned... Excuse me, preserved with that method because of acidity, and which ones have the potential for botulism growth.

So the removal of oxygen, anaerobic, is definitely a way that we do preserve our food, but one has to be very understanding and careful when you choose to use those methods and really understanding the science behind that. So we also have, when you're fermenting food, now this is where we're using, again from fermented food, is using multiple ways to actually preserve the food. So you have, initially with many of your ferments, you are using a saltwater brine and or you're salting the cabbage. So for when we're doing sauerkraut or cortido, which is my favorite version of sauerkraut, it's a Spanish version of sauerkraut, we aren't making a saltwater brine, but we are salting the vegetable, which is pulling out the extra liquid from the actual vegetable, and it is creating a brine in a liquid level. Then when we're packing it into either our fermenting crock or our jar, we're using a weight to make sure that all of the solids are pushed beneath the liquid level so that they don't mold.

So we are using an anaerobic environment basically, because we're keeping it away from being exposed to air, in that we're using the salt, which is also going to help balance and keep some of the bad organisms from taking over, especially salt, like in the case of when we're doing lacto-ferment, it's a balanced on only between bacteria, good bacteria versus bad bacteria, but also yeast, right? So you've got that in the air, and so the salt helps to keep that at bay until we have reached a good balance and we actually have acid come into play, which has lactic acid bacteria when we're talking about ferments. And then some ferments will even go further and ferment into an alcoholic state, which that can't when we're talking vinegars and some fruits, et cetera, other things like that. And that is also another form of food preservation, but it's using multiple methods in order to create a food that is preserved and is safe for us to then consume.

Now the good news is we have many of these methods available to us, and we can combine them with these forms of home food preservation to truly create a food security system and a food storage system at home. And the good news is when you're using multiple forms of food preservation, which I highly recommend, not just relying on one, then you're able to have a very good variety, because we really do need to have a variety in our foods that we're eating. And because it is not safe to use every form of food preservation for every type of food. There are some foods that you can't even pressure can, there's some vegetables that should not be pressure canned. One of those is straight summer squash, so zucchini, in the 1990s, they did further testing, again, here's that science, and zucchini specifically was removed, I want to say in 1996, but it was in the '90s, from being recommended to can at home. Now relish and pickled zucchini is fine. That's water bath and we're acidifying it, but straight pressure canning it is not recommended because it gets too mushy.

Not a big surprise there with zucchini, and the heat can't penetrate all the way through the jar evenly to ensure that any spores that may be in their would fully be killed. Broccoli is not something that we pressure can, but there's other ways that we can preserve broccoli. So it's really important that you know all of the ways that are available to you that are safe for each food type. And it's also important that you have a food preservation plan in place so that you're taking full advantage of either the food coming out of your own garden, farmer's markets when it's local, in season, purchasing it wherever you're getting it from, maybe it's a local farmer or you-pick farms, but that you've got this plan in place, so you know, one, the way that those foods can safely be preserved, the way that your family likes to eat them and consume them, the way that you're going to be cooking them or eating them, so that you're preserving them in a way that you're actually going to use and people in your family are going to eat.

Can I get an amen here? And then that you have the skillsets and the knowledge to use that particular form of food preservation in a safe manner, that you're understanding it. Then fourthly, that you have whatever supplies may be needed, because some forms of food preservation require more equipment than others, that you know what those are, where to get them, what ones are essential, and then as I said, you have the skillsets to actually put them into use. Which is why I'm doing my free class, which I told you at the beginning of this podcast episode. And that's how to create a food presence plan so that you can save more food with less stress. So sag your seat, melissaknorris.com/harvestplan. It's going to be a fabulous class. We're going to dive into this in a deeper way than we even had right now in today's episode. So think of this as your primer.

Now onto our verse of the week. This is from 1 John 5:21, "Little children keep yourselves from idols. Amen." Now that's pretty short and sweet. And I have to confess too, when I was younger and I heard verses about idols, my brain and my mind always went to, "Well, I don't wish idols, we don't do idolatry. I'm not bowing down to a statue. I'm not praying to a picture or something that I've created out in nature," all the different forums that literally idols can take. And so it wasn't until later in life, thankfully, as most of us, as we get older in life, we do start to gain a bit more wisdom and understanding. And I realized that an idol, though yes, it can be in a very literal sense, it also is anything that we are placing above the Lord. So if we're placing that above our relationship with Jesus, or we're allowing it to have too much of importance to us, we're relying on it.

I mean, there's lots of things, really anything, and or person could become an idol. Sometimes it can be careers, it can be a relationship, but it's anything that we're putting before the Lord or we're giving more importance to than we are to Him. And I know that many of you who listened to this podcast are already Christians and already you know a lot of these verses, but I thought it was really important for me because sometimes, I can let things start to gain no more importance. And it's that slippery slope thing, where I don't really realize it, it's happened slowly and gradually over time, that there are things that I am allowing, and it's me, I'm allowing them, and or my desires, for certain things to have a spot before the Lord.

And they're becoming too important to me and they are affecting me. They can even be good things, but if they're shifting minds focused so much to those things only, or having me strive towards those things more so than I am with my walk with the Lord, then those can be an idol or have the potential, or we're getting real borderline. And so I share that with you because I'm at a point where I am feeling a lot more at peace by just giving them to the Lord. And I know that sometimes when you hear that, you're like, "Well, that's great." But really, there's been things where I have really strived and struggled or I've had desires that I wanted so badly, and they aren't bad things. They're not bad things by any way, shape or form, but my deep-seated desire on wanting those things was where the issue lies. And so I'm laying them at His feet again. And I've had to do this multiple times in my life with multiple different things.

One of the most notable was my wanting to become an author. I knew I wanted to be a writer from the time I was eight years old and a very little girl, but I wanted to be a published author by a traditional publishing company so bad. And I remember, it was just like I dreamed it, I tasted it, it was like all I could think about, and it didn't happen. And it wasn't until I finally laid it at God's feet and said, "Okay, Lord, if this is something that you want to happen for me, then you'll make that, but if it's not, I need you to take away this desire and help me to be at peace and to show me what it is You would have me do. I'm willing to lay this down, to truly give it away and to stop pursuing this if that's what You would have me do." So I was willing to be Your will not mine, basically is what it boiled down to.

And when I finally did that and meant it from a true sincerity in my heart, that was when doors started opening that I had been trying to open on my own. You guys, I sought publication and had literary agents for fiction and writing for over 15 years. So it was a long thing, but doors that were never opening for me and things that were never go in that direction, and once I really, truly did that with sincerity, that's when I got my book deal, my very first book deal, which was The Made-from-Scratch Life. And that's when publishing opened, and now I have four books out. But I just shared that with you, because even though that is not an idol for me right now, there are other areas in my life that I noticed were almost coming to that same point, and that I needed to lay them at His feet, not so that they would happen, because that's not my goal with telling you this story, but that so I am remembering to keep Him first and to be at peace and to make sure that I'm walking in His will and not my own.

So I hope that that provides you with some inspiration and maybe some food for thought, some reflection, that type of a thing, which is my goal always, with sharing you those verse of the weeks and some things that I'm struggling with in my own life. Now, I can't wait to be back here with you next week, because we have a very special guest coming on and it is really an amazing episode. So go get yourself signed up for the free class, melissaknorris.com/harvestplan. And then I will be back here with you next Friday for a podcast episode interview with Joel Salitan. Blessings in Mason jars for now my friend.