Blackberry and Elderberry jellies

A year on and it's jelly-making time again!

This time, I used recipies from the book "The right way to make jams" by Cyril Grange Frhs.

On Saturday, I picked 2.5kg of blackberries and 750g of elderberries (with stalks). I also bought 1.6kg of Bramley apples.

The book suggests to add 25% of water to blackberries, and 50%-100% of water to the elderberries and apples (depending how you read the recipe). After boiling for 1h, I ended up with 2.0l of blackberry juice, 820ml of elderberry juice and 1.0l of apple juice.

The recipies I decided to make were:

Source Fruit Apples Sugar (per juice) Juice of lemons (per litre) Bottles of Certo (per litre)
Blackberry Apple TRWTMJ 75% 25% 75% - -
Blackberry Apple Certo 40% 60% 170% 1/3 1/2
Elderberry Apple TRWTMJ 50% 50% 75% - -
Elderberry Certo 100% - 230% 3/4 1.5
To convert weights into volumes, I measured the specific weight of fruit juice at 1.01kg/l.

Strictly, the juice from 833g of apples was for the blackberries and the juice from 750g of apples for the elderberries, equating to 520ml of juice for the blackberries and 480ml for the elderberries, but I ended up adding 655ml to the blackberries and only 345ml to the elderberries. I now had 2.7l of blackberry/apple mixture and 1.2l of elderberry/apple mixture. The pectin tests using methylated spirit for these mixtures were positive as far as I could tell.

The mixtures and respective results I ended up with are:

Batch Juice Sugar (per juice) Juice of lemons (per litre) Bottles of Certo (per litre) Result
Blackberry apple B1 1.3l 75% - 1/5 6 jars, set perfectly
Blackberry apple B2 670ml 150% 3/4 3/4 3 jars, set firmly
Blackberry apple B3 700ml 75% 3/4 3/4 3 jars
Elderberry apple E1 1.2l 75% - 1/5 4 jars, didn't set
Elderberry apple E2 600ml 205% 3/4 - 3 jars, set gooey
Elderberry apple E3 600ml 75% 3/4 3/4 2 jars, didn't set
Elderberry apple E4 600ml 125% 3/4 3/4 3 jars

Batches B1, B3, E1 and E2 were boiled rolling for 12 minutes after adding the sugar as instructed in TRWMTJ. Batches B2 and E3 were brought to boiling after adding lemon and sugar and boiled rolling for 30 seconds to 1 minute after adding the Certo, as stated in the Certo recipes.

Next time, I'd like to use a strategy where I make a small amount first to verify the properties of the fruit and all ingredients.

I'd also like to try extracting the juice from the berries and apples together as described by the blackberry and apple recipes in TRWTMJ and Certo, rather than separately (as prescribed by the elderberry/apple recipe in TRWTMJ). I should also experiment with adding lemon juice, pith or whole lemons at the start of the juice extraction.