Place 3-4 spoons in freezer to chill. These will be used to test the doneness of jam later.
In a large, heavy bottom pan, add strawberries, sugar, salt, lemon rind and lemon juice together to cook on slow flame.
Allow it to cook on a slow flame bringing it to a boil.
To reach a chunky consistency, you may need to mash the strawberries lightly using a potato masher.
Alternatively you can use pureed strawberries in place of mashed if you do not like chunks in your jam.
Continue to stir as the jam thickens and reduces.
The bubbles which will form upon cooking, will also start to reduce in size and become thicker.
This should take from 10 - 30 minutes depending upon the size of the flame.
For me it took me 25-30 minutes to reach as I cooked it entirely on slow flame.
Bring out one of the chilled spoon and place a few drops of jam on it, and wait for a few seconds.
Run a finger through the blob of jam in the spoon, and if it makes a clear path and doesn't come back, the jam is cooked.
If it comes back, then cook the jam for another few minutes and repeat the check with a fresh chilled spoon.
To sterilize the Jar
Wash the jars and preheat the oven to 160°C.
Keep the jars in the oven for about 20 minutes. Pour hot jam in hot jars.
Remember to pour hot jam in hot jar and not hot jam in cold jars. Do Not pour hot jam in cold jars. The glass will shatter due to temperature difference.
Seal jars when they both reach room temperature. It will stay refrigerated for 4-5 weeks.