Jam making1
Jam making
Principles of jam-making
Micro-organisms are destroyed as fruit is heated to 100⁰C.
Sixty-five per cent sugars are added, which acts as a preservative and prevents microbial growth of the fruit. Pectin and acids help the jam set.
Sealing prevents the re-entry of micro-organisms.
The ingredients used in jam-making are fruit, sugar, pectin and acid.
Too much sugar = Crystallisation
Too little sugar = fermentation
(Store jams completely covered in a cool place)
Fruit
Sugar
Pectin
Acid
Use ripe fruit
Fruit high in pectin
Acidic fruit
Examples include blackcurrants and cooking apples.
Needs to be accurately weighed. Too much causes crystallisation.
Warmed sugar will dissolve quickly.
Granulated sugar is generally used.
Sure-set sugar is ideal for jam-making (boil for 4 minutes -> it has extra pectin added to help setting)
This is a polysaccharide
It is found in the cell walls of ripe fruit.
Pectin affects the setting quality of the jam.
Releases pectin from the cell walls of the fruit as the fruit softens.
Gives a good colour and flavour to jam.
Acid prevents crystals forming.
Lemon juice is commonly added.
A closer look at pectin
Pectin = carbohydrate -> Polysaccharides
Using lemon juice helps to draw the pectin from the cell wall.
Under-ripe fruit
Ripe fruit
Over-ripe fruit
Pectose (protopectin) Poor setting quality
Pectin
Good setting quality
Pectic acid
Poor setting quality
Levels of pectin in different fruits
Good levels of pectin
Medium level of pectin
Poor level of pectin
Apples
Oranges
Blackcurrants
Plums
Apricots
Raspberries
Strawberries
Cherries
Pears
Testing for pectin in fruit
Place one teaspoon of fruit juice into a small glass.
Add three teaspoons of methylated spirits
Mix together and leave for one minute.
Poor from one glass into another glass.
Results
One firm clot = high in pectin
Three/four smaller clots = medium amount of pectin
Lots of smaller clots = poor
Principles of jam-making
Micro-organisms are destroyed as fruit is heated to 100⁰C.
Sixty-five per cent sugars are added, which acts as a preservative and prevents microbial growth of the fruit. Pectin and acids help the jam set.
Sealing prevents the re-entry of micro-organisms.
The ingredients used in jam-making are fruit, sugar, pectin and acid.
Too much sugar = Crystallisation
Too little sugar = fermentation
(Store jams completely covered in a cool place)
Fruit
Sugar
Pectin
Acid
Use ripe fruit
Fruit high in pectin
Acidic fruit
Examples include blackcurrants and cooking apples.
Needs to be accurately weighed. Too much causes crystallisation.
Warmed sugar will dissolve quickly.
Granulated sugar is generally used.
Sure-set sugar is ideal for jam-making (boil for 4 minutes -> it has extra pectin added to help setting)
This is a polysaccharide
It is found in the cell walls of ripe fruit.
Pectin affects the setting quality of the jam.
Releases pectin from the cell walls of the fruit as the fruit softens.
Gives a good colour and flavour to jam.
Acid prevents crystals forming.
Lemon juice is commonly added.
A closer look at pectin
Pectin = carbohydrate -> Polysaccharides
Using lemon juice helps to draw the pectin from the cell wall.
Under-ripe fruit
Ripe fruit
Over-ripe fruit
Pectose (protopectin) Poor setting quality
Pectin
Good setting quality
Pectic acid
Poor setting quality
Levels of pectin in different fruits
Good levels of pectin
Medium level of pectin
Poor level of pectin
Apples
Oranges
Blackcurrants
Plums
Apricots
Raspberries
Strawberries
Cherries
Pears
Testing for pectin in fruit
Place one teaspoon of fruit juice into a small glass.
Add three teaspoons of methylated spirits
Mix together and leave for one minute.
Poor from one glass into another glass.
Results
One firm clot = high in pectin
Three/four smaller clots = medium amount of pectin
Lots of smaller clots = poor