Preparing preserves is a way to take advantage of the harvest from the home garden or, why not, the market offers, but you have to prepare them thoroughly respecting each step so that the result is safe.
No matter how much the world and technology advance, today, like yesterday, we still want to enjoy home canning, taking advantage of seasonal fruit and vegetables to consume throughout the year. The preservation techniques are various, from dehydration, lacto fermentation, vacuum or canned water in a water bath as in the past, which we are going to focus on in this article.
6 TIPS FOR SAFER HOME CANNING
Whether for jams or fruit compotes or canned tomato sauces or boiled vegetables, the sterilization phase of the jars is the most important of the process because it is where we most guarantee the absence of risks and germs, although the cleanliness and quality of all the elements must exist at all times.
1. CHOOSE FOOD IN PERFECT CONDITION AND WASH IT WELL
Extreme hygiene in each processing step to prevent the multiplication of some bacteria that can be toxic. This includes washing the products, the work surfaces and the instruments that we use.
2. CHECK THE GLASS JARS THAT WE WILL USE AND DISINFECT THEM
They can be washed by hand with soap and water, but more efficiently in the dishwasher, the oven or, if they are reused and not new, by boiling them in a saucepan covered with water, for about 20 minutes after boiling.
Cleaning in the oven consists of placing the clean and dry glass jars in the tray with the oven previously preheated to 170 ºC and leaving them there for about 10 minutes.
To preserve the jams, small jars are recommended because they cool before and they keep better. If they have a wide mouth, the handling is easier.
3. MAKE SURE THE CANNING IS WELL COVERED
The lids require special attention because they must close hermetically, without leaks for the correct conservation of the preserve. Ideally, use new caps and clean them well. If they are old, they should be boiled like jars. There are 3 types of tapas to value:
- The classic thread
- Those that include a sealing button in the center of the lid. Once the vacuum is made, the button is partially sunk inwards.
- The glass lids with staples and sealing rubber in which it is easy to check whether they work or not because when the staples are opened the lid remains well attached if the vacuum has been produced correctly.
4. CARRY OUT A CORRECT FILLING
When filling the jars with jam or preserves, we must be careful not to burn ourselves. The funnels adaptable to the jars make this task much easier by avoiding spills and risks.
The jars should be filled almost completely to prevent environmental bacteria from entering, but leaving a small space near the rim so that a vacuum can be made.
Although it is popularly considered that filling the jars with very hot jam or sauce is enough because the heat destroys the germs and the vacuum is made when the container is turned over, for greater safety we recommend boiling the jars later to achieve higher temperatures.
5. APPLY THE STERILIZING HEAT WELL
The last part of the process is the most important because it is where we play conservation the most.
The traditional and simple method by applying heat is the so-called “water bath” and consists of exposing the products to be preserved to a temperature higher than 70-90 ºC, with which most of the germs and bacteria responsible for the fermentation or from rotting food are destroyed.
A cloth rag can be placed between the cans inside the pot to avoid friction between them and possible breakage due to thermal shock, although this is not usually necessary.
It is advisable to remove the preserves after boiling and avoid leaving them in the pan because some microorganisms have their best development point with temperatures between 40 and 70º. We are looking for rapid cooling.
When taking them out, we put them upside down on some rags or cardboard to check if any of them have not been well sealed and liquid comes out. If so, the vacuum has not been made and it should be stored in the fridge and consumed in the following days.
To help us get the cans out of the boiling water there are specific tongs for canning. We can also use heat resistant kitchen gloves, although sometimes they do not allow a good grip. Be careful.
CAN WE USE THE PRESSURE COOKER?
Although it is not the most widely used option, with the pressure cooker we achieve better hygiene and conservation results. In his book Natural preserves, the expert Mariano Bueno explains that it is one of the safest methods for a good sterilization because when the pressure increases, the temperature easily reaches between 120 and 160 ºC and under these conditions the preserves can be completely sterilized and minimizes the risk of Clostridium botulin, the dreaded cause of botulism.
In these pots, it is advisable to isolate the jars from the bottom with a cloth or a rack and use 10 to 20 minutes after the steam has come out for proper sterilization.
THE ELECTRIC PASTEURIZER
There are also specific appliances for boiling canned food such as pasteurizers, which have advantages over conventional pans due to their larger size, temperature control, cleaning because splashing is avoided, efficiency and safety.
The pasteurizers are programmed, they turn off automatically and have a small tap for the water outlet.
In addition to pasteurizing preserves, they are also used to prepare broths and stews or stews.
6. LABEL THE PRESERVES
We must not forget to label our jars to identify what they are and the date of production, because sometimes several harvests come together and we must always give priority to the previous ones.
HOW TO AVOID BOTULISM AND CONTAMINATION
Canned food safety is a recurring theme because there are different microorganisms that can cause food spoilage such as yeasts, molds and bacteria, but the latter are the great threat to our canned food as they are resistant to heat.
Molds and yeasts die from 60º, but bacteria withstand higher temperatures and thrive, without the need for oxygen, in low-acid (alkaline), humid and closed environments, such as those found in canning containers. Hence the need to respect all the phases of the process and sterilize at high temperature, first the empty containers and then with the preserves inside.
The scariest disease when dealing with these issues is botulism, caused by a toxin produced by the bacterium Clostridium botulin. This toxin can be found in poorly prepared canned food, both in a water bath or by vacuum systems, in low-acid canned foods that have been subjected to inadequate heat treatment, in some meat products, non-chlorinated waters or by inhalation.
Preserves that have a swollen lid that give off strange odors, that make a kind of foam or that gas comes out when opened should be ruled out without hesitation.
ENJOY CANNING FOR MONTHS
It is recommended to store home canning in a dark, cool and dry place because humidity promotes mold growth.
In general, they keep perfectly for more than a year and some much longer, but each case must be evaluated because low-sugar jams and compotes have a shorter shelf life.
Once opened, the preserves are exposed to environmental bacteria, so they must be consumed in a few weeks and always stored in the refrigerator.
With all these tips, today, as in grandmother’s time, we can continue to enjoy seasonal fruit jams for the rest of the year.