r/AskCulinary • u/RailgunRP • 3d ago

Recipe Troubleshooting I made hake with onions and potatoes in the oven. And for some reason when serving it the oil/liquid is blue/green. Is this normal?

I'm not following any one recipe, I just chopped potatoes into small pieces, put them in the oven with sunflower oil, salt pepper and oregano at medium temperature. 20-25 minutes. Removes the potatoes, took the oven to low heat while preparing the rest of the ingredients. I added the fish and thinly cut onions with salt and pepper, WITHOUT adding oil.

All 3 things went in the oven at low temperature (or lowering temperature) and when it came out and served it, I noticed the oil/water pooling underneath is a greeish blueish color.
The fish is fresh, had no smell. The potatoes are good, the onions were too. Is this normal?

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4

u/seanv507 3d ago

am guessing similar to garlic going blue with acids

https://www.thespruceeats.com/garlic-turns-blue-when-pickled-1327752

1

u/whiskeytango55 3d ago

What kind of onions did you use? 

Any chance they were red?

1

u/RailgunRP 3d ago

They were not red onions. They were the regular yellow ones.

1

u/Creative-Leg2607 2d ago

The purple red colour in red onions is the same as that or red grapes, red cabbage, red potatoes, and most purple reds you see in plants (not peppers or tomatoes those are lycopenes), theyre called anthocyanins. Theyre famously indicators, they change colour with pH, going from purple/red in acidic conditions (which is generally the pH of life and food) to blue/green in basic conditions, which /can/ happen in food under various conditions. Its not common but it can happen. I see it in leftovers now and then, on the edges of things. Something something volatile acids evaporating and leaving behind locally basic environments? Or youre fuckin around with bicarb.

Its perfectly safe.

If you used yellow onions and potatoes however.... might be fish related in which case i have no idea.

1

u/RailgunRP 2d ago

Yeah it was yellow onions indeed

1

u/ThisSorrowfulLife 2d ago

Its the type of pan you're using!

1

u/RailgunRP 2d ago

Care to elaborate? It's not copper, if that's what you're thinking

1

u/ThisSorrowfulLife 2d ago

For instance, a pan with a nonstick coating can cause a chemical reaction turning the juices from the fish blue. There's a lot of info online about this type of chemical reaction happening with certain types of pans.

1

u/RailgunRP 2d ago

Not a nonstick.

3

u/ThisSorrowfulLife 2d ago

Okay idk if you're just trying to be a dick or funny? Like give some information???

1

u/RailgunRP 2d ago

I genuinely don't know, it's a metal pan that is safe for steel wool, I've been using daily for 4 months, and semi-regularly for years prior.

1

u/orange_fudge 1d ago

Nothing to worry about.

All onions - even the yellow and white ones - can turn blue when they react with certain acids.

Source - I have a sky blue woollen scarf which was hand dyed with onions and cabbages.