Lemon juice in jam recipes

[lillian]

I'm in the mood for making  microwave strawberry jam making. Some recipes have lemon juice, some do not. Any idea why lemon juice is used? x

[lillian]

[Sparkly]

This is to do with the acidity levels which are required to allow the jam to set. Some fruits are high in acid already, but others like strawberries are not.

[Sparkly]

If you are interested in the science it is because the pectin is a carbohydrate; like starch It has a very coiled structure. When it is heated it is able to absorb water molecules which makes the solution thicker (into a gel). It is to do with hydrogen bonds forming between the sugar molecules in the strands of the pectin molecules making them stick together in a network. This process requires quite a low pH as this affects the charges of some of the additional molecules found within the pectin structure (it isn't just sugars it has some ions etc like salts e.g calcium). It's quite alot more complicated than that, but that is the basics.

[manicscousers]

This is to do with the acidity levels which are required to allow the jam to set. Some fruits are high in acid already, but others like strawberries are not.

and it gives it a nice tang  :)

[tricia]

I made microwave strawberry jam just this week and added a level teaspoon of citric acid (pharmacy) to 500g fruit. You could also add the juice of half a lemon, but I think it would act better if you cooked some juice with the peel first (in the microwave, of course!) before adding it to the jam. Be sure to use a high sided glass container - the jam rose almost to the top of my 2 litre Pyrex jug

It's lovely - good luck!

Tricia

[Jeannine]

Manics, you have cracked me up laughing and my ribs hurt XX Jeanninme

[susan1]

I made some strawberry jam on Saturday added the lemon juice, used preserving sugar, and used a full bottle of pectin and boiled it till it got to 105 degrees, but it still hasn't set  :( any ideas how I can rectify this. Could always use some as a coulis I spose but 8 jars of the stuff not set is beyond a joke.

[pumkinlover]

If you are interested in the science it is because the pectin is a carbohydrate; like starch It has a very coiled structure. When it is heated it is able to absorb water molecules which makes the solution thicker (into a gel). It is to do with hydrogen bonds forming between the sugar molecules in the strands of the pectin molecules making them stick together in a network. This process requires quite a low pH as this affects the charges of some of the additional molecules found within the pectin structure (it isn't just sugars it has some ions etc like salts e.g calcium). It's quite alot more complicated than that, but that is the basics.

That was really interesting Sparkly, the depth of knowledge on this forum never ceases to amaze me :)
and put over so it is understandable.

I wondered if the amount of rain would make the strawberry water content so high that it has to be removed before the jam can set. :-\

[petengade]

I made some strawberry jam on Saturday added the lemon juice, used preserving sugar, and used a full bottle of pectin and boiled it till it got to 105 degrees, but it still hasn't set  :( any ideas how I can rectify this. Could always use some as a coulis I spose but 8 jars of the stuff not set is beyond a joke.

Had the same problen Susan1 bunged it all back into pan, heated up to jam set again, gave it another seven minutes, perfect set.

Tried the granny recipe below with the next batch adding rhubarb and using granulated sugar (not jam sugar), perfect set, cannot taste the rhubarb
http://mariedwivkidz.hubpages.com/hub/Strawberry-Jam-that-sets

[Jeannine]

Petingade if yu use Certo  liquid pectin you only have to bring you fruit and sugar to the boil add the Certo boil for 1 minute more  only and it is done, you don;t have to keep boiling it, thay is the beauty of Certo liquid. You don't need to check the temp and if you overboil it it won;t set..1 minute only!!

XX Jeannine

[antipodes]

A lot of people like my jam (I say modestly)... and it is always well set, not liquid like a lot of people's. Well, I think my secret is in correctly cooking the fruit before adding the sugar. I never use jam sugar, just ordinary and nothing added, except lemon juice. I make sure that the fruits is quite reduced before adding the sugar (some recipes call for too much water added to the fruit beforehand!), then I boil like mad for a good 10-15 minutes. When the mixture will drop onto a plate and start to "gel", then it is ready enough for me.

[petengade]

Petingade if yu use Certo  liquid pectin you only have to bring you fruit and sugar to the boil add the Certo boil for 1 minute more  only and it is done, you don;t have to keep boiling it, thay is the beauty of Certo liquid. You don't need to check the temp and if you overboil it it won;t set..1 minute only!!

XX Jeannine

Thanks Jeanine, have Certo in the cupboard will give it a try.
I think Antipodes has the answer also.

[susan1]

Many thanks pentengade, I did as you said and bunged it back in the pan and boiled for 7 mins after I achieved temp, perfect set now :)

[Jeannine]

When I was in the UK I bought liquid Certo but can't remember if they had the powdered form also as I never use it.

Here there is a difference betwen the two.

Powdered goes in WITH the sugar and the mixture is brought up to a boil.

Liquid goes in WHEN THE MIXTURE is boiling and  then you time  for just 1 minute

If you follow the recipe for the powered one but use the liquid one and vica versa it affects the setting considerably.

I use liquid Certo in all my jam and jelly recipes beacuse I don't like the long boil that is needed without it, I find the taste with it is fresher and much more fruity.

XX Jeannine

[Borlotti]

I added redcurrants to my jam, and lemon juice, and have lovely strawberry and raspberry jam (no lemon in the raspberry, just a few redcurrants), and it set, not too firm and not too runny.  OH has put a label on it, as he said it is very addictive.  Have even given some away.  Have got a very big pot, from Morrisons, and that is better than burning out saucepans like I did last year. With the raspberry jam heating the raspberries first for 10 mins, then added sugar and then fast boiled for 5 mins, and it is beautiful.  ;D ;D

[susan1]

Jeannine, I think that's where I may have gone wrong I put the liquid pectin in with the fruit, as I got from a recipie on the net, should just stick to my books lol, my next lot of jam Wil Be blackcurrAnts in the next few days or so, haven't looked at them for a few days

[Debs]

Hi susan1,

For strawberry Jam I use Delia's tip - make sure the strawberries are dry, cover them with the sugar & leave overnight as this helps to keep the fruit whole during the jam making process
Boil up for 8 mins & test for setting point.
To test: put a saucer in the freezer until v.cold & drop jam on to it. Jam should crinkle & not run.  Boil for further 8 mins if not set

Debs

[susan1]

thanks debs, i will try that next time, reboiled yesterday as advised by pentengade and its set perfectly now, had some on toast for breckie this morning was yummy  :)

[Jeannine]

Susan, you can't go wrong if you follow the recipes that come with Certo or go online to Certo UK. The  liquid here in North America comes in sachets which are a slightly different size than what the UK bottles hold. I remember when in the UK for a few years it drove me nuts as all my recipes where based on the sachets. I did work in out in the end.

If you want to use a US or Canadaian recipe bear in mind that a sachet of liquid  Certo is 85ml.

Strawberry  therefore would be 3 3/4 crushed strawberries(using a 250 ml cup) 1/4 cup lemon juice,7 cups of sugar and 1 sachet of liquid Certo.

Put in pan, crushed fruit, sugar and lemon juice.Bring to a rolling  over high heat,Add liquid Certo, count 1 minute only . Remove from heat and skim.
That's it.

Drop dead easy.

If using the bottle Certo adjust as needed to giive the righ ratio. I forget what the bottle contains, sorry.

XX Jeannine

[antipodes]

Last night I made gooseberry/rhubarb jam. I used: 1.5kgs gooseberry, 300g of rhubarb, and half a cup of water as the goosegogs give out a lot of juice. I cooked the fruit for a fair while, at least 35 minutes until it was a nice wet pulp, then I added 1.4kg of sugar. No lemon, I forgot it  ;D  And boiled for about 12 minutes, until a blob dropped on a plate was jelly like.
Made 8 jars and this morning the set is just right.
It's a good combination, if you like tartness, as when you bite into some of the gooseberry pieces they still have strong flavoured juice in them!