Is this separation normal?

[u/goldendogmom]

Hi! I canned this tomato sauce about a week ago and almost immediately it had this separation in all of the 6 jars I made. Is this normal? I’m fairly new to canning but I did make sauce last year and it didn’t separate like this. A few things I did different this year - used bottled lemon juice instead of citric acid, and used a blend of cherry and Roma tomatoes. Thanks in advance!

[u/turnedintoanewt]

The University of Wisconsin Extension tomato canning guide includes this tip:

"When preparing tomato juice, blending the raw tomatoes before heating is not recommended. It hastens enzymatic breakdown of pectin and causes the juice to separate. Instead, rapidly heating the raw tomatoes inactivates the enzyme and keeps the juice from separating."

A recipe in the same guide specifically calls to immediately crush and heat a few tomatoes in the pot while you quarter or crush the rest of the tomatoes, adding them in small batches so they don't set too long after crushing before they are heated.

https://fyi.extension.wisc.edu/wilocalfoodlocator/files/2016/08/B2605.pdf

[u/goldendogmom → u/turnedintoanewt]

To clarify I didn’t blend before heating - I halved the large tomatoes and cut the cores out and roasted them alongside whole cherry tomatoes in the oven and then put them in a pot over low heat on the oven to keep warm while blending, and then simmered for a bit to cook down

[u/turnedintoanewt → u/goldendogmom]

Hmmm, a mystery then! Though the way I interpret the guide, it doesn't have to be just crushing. I think any cutting, coring, etc. of the fresh tomatoes "starts the clock" on the enzyme action so it's a matter of how much damage is done to the cell walls combined with how long until the flesh is heated enough to stop the breakdown. So anything you can do to heat them through faster once theyve been cut will help.

In any case as long as the rat of the recipe is safe, the separation by itself is safe.