Why can't I scale up jam/jelly recipes?
Pectin packages always explicitly state that jelly/jam recipes cannot be scaled up.
My own empirical evidence is limited but I did have a doubled batch not set so I no longer double the batches.
What is it about
((pectin + acid + sugar + water) * boiling) = jelly
that makes scaling impossible?
Best Answer
I haven't made jam in years and don't know first-hand, but this website suggests it won't scale as the jam won't cook as well. This seems predicated on the idea that your cooking vessel remains the same size but the batch is larger.
From the linked site:
Most jam recipes already call for you to use the widest pot you have, for maximum surface area. This large surface area leads to faster evaporation of water. Fast cooking leads to the freshest tasting, best textured jam.
However, if you double the amount of jam in your pot, you greatly increase the cooking time, because there’s so much more product in the pot that needs to be cooked down. This can lead to rubbery batches, burning and jam that doesn’t set.
This is also supported by another site that claims doubling is difficult "due to inherently uneven heating of home cookware".
Per nico's comment, it sounds like doubling/scaling is possible - perhaps give it a try in cookware appropriate to the doubled batch size.
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How do you reset jelly?
To remake uncooked jelly or jam with powdered pectin measure jam or jelly to be remade. Work with 2 L (8 cups) at a time. Mix jam or jelly with 25 mL (2 tbsp) sugar for each 250 mL (1 cup) of jam or jelly. Stir well until dissolved about 3 minutes.Is it OK to double a batch of jam?
Making a double batch of jam or jelly is not recommended because it will not consistently gel properly if you try to double the recipe or make larger batches. It also takes longer to cook, is more likely to burn, and the consistency may change. Jams and jellies should always be made in small batches.The Chainsmokers, Bob Moses - Why Can't You Wait (Official Audio)
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Answer 2
Scaling is difficult, as the ratio of ingredients changes with the batch size. Acid and pectin levels need to be altered to create proper gel formation.
Answer 3
Because of time considerations ?
I made a 1 and 1/3 recipe last night which seemed to work well even though I accidentally made a couple mistakes (like I forgot to put in the last 2/3 cup of sugar & mixed half a pkg of 1 brand pectin with an eyeballed "half" of different brand that I had just bought...etc.)
Larger scaling, like double, I have never tried, but I thought it was discouraged because of the timing with hand canning: You will either have to leave the extra jam in the pot twice as long with the fire off, potentially getting cool; or keep it cooking the whole time, and it may over-thicken.
The ingredient ratios themselves really can't be all that exacting, or recipes would routinely fail due to years of slightly sweeter, juicier, or tart-er fruit, or different varieties of trees, etc. Not to mention forgetting abt. 6% of the sugar, which didn't seem to matter at all.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: EKATERINA BOLOVTSOVA, Pixabay, Nilina, Pixabay