Bitter aftertaste in apple butter?
November 10, 2012 6:38 PM   Subscribe

I just made a large batch of apple butter (~8 pecks) in a giant uncoated copper kettle, cooked on top of a wood fire for the better part of the day. The texture is great, but there is a bitter aftertaste (stronger in some parts, like those from the side of the pot, than others) that slightly worries me — what could have caused it, and is it plausibly safe to eat?

Sorry in advance for all the details in what boils down (ha) to a "can I eat it?" question, but I'd like to figure out what exactly is going on if possible.

A few possible explanations that I can think of:

1) Leached copper. The bitterness does not taste particularly metallic to me, but I would not be surprised if some amount of copper leached in during cooking.

The kettle is an antique, so had not been used for at least one or two generations. It was originally fairly dirty and tarnished, so I thoroughly scrubbed it with Brasso, then Barkeeper's Friend, and then dish detergent (with plenty of rinsing after each). At the end of cleaning, it was fairly shiny though still had several blackened areas that I could not remove (wood had previously been burnt inside the kettle, probably causing these marks).

Before cooking the apple butter, I also boiled about 2 inches of water in the pot as a final cleaning step and sloshed it around the sides. More of the tarnish disappeared, and the water turned kind of golden. In retrospect, that color change is a little unsettling... but making apple butter is what the kettle is for! So I continued anyways.

One last observation I made, to make things even more unappetizing: after removing the boiled water, and before adding the apples, the hottest part of the empty kettle bottom turned an iridescent blue surrounded by purple and other colors, looking kind of like a gasoline spill sunset. Beautiful— but, food-safe?

2) Peels and/or seeds. Maybe 5% of the total peel, and maybe ten or so seeds probably made it in. We added no extra sugar, so any bitterness from these would probably show through.

3) Smoke, ash. There was plenty of smoke going around as the breeze shifted directions, so some of the acridness could have made its way in.

4) Burning. A small area at the center of the bottom of the pot turned black from where the apple butter burned just a little.

From my framing of the question, perhaps you can tell that my main concern here is trying to convince myself that the apple butter does not contain unsafe levels of copper. I realize that no one can give me a definitive answer, and it is better to err on the side of caution, but if anyone has any experience with something like this, or can think of any tests I can do to narrow things down (other than eating all of it and waiting to see what happens), I'd appreciate your thoughts. Thanks.
posted by caaaaaam to Food & Drink (9 answers total) 1 user marked this as a favorite
You can test it for copper using a test kit (this one is for illustration; I haven't used it).
posted by zug at 6:43 PM on November 10, 2012

Best answer: I was just thinking, "I've seen something similar lately," and it turns out to have been here!

posted by something something at 6:44 PM on November 10, 2012

Best answer: The burning could definitely taint a whole kettle. I don't have experience with apple butter, but I've burned my share of soups and stews. If you stir up the burnt part it will impart bitterness.

The rainbow iridescence, I'd seen in my stainless steel pots. I don't think that means anything.
posted by cabingirl at 6:45 PM on November 10, 2012

Ten seeds doesn't sound like too much but just as an FYI, you know that apple seeds have a tiny amount of cyanide in them, right? I haven't gone looking but I've never heard of anyone being poisoned by apple seeds left in food, though.

(It looks like this comment may have gotten deleted but I am not joking; apple seeds and many other seeds and pits from plants do actually have cyanide in them—see here for example—and have a bitter taste like the OP describes.)
posted by XMLicious at 7:33 PM on November 10, 2012

It sounds like a classic case of scorch to me. Scorching on the bottom of the pot can easily ruin a whole batch of food.
posted by SweetTeaAndABiscuit at 7:45 PM on November 10, 2012 [3 favorites]

Copper is a reactive metal. There's a possibility that it made the acid in the apples bitter.
posted by girih knot at 9:43 PM on November 10, 2012

On further research, if that kettle wasn't lined with any other metal, you shouldn't eat that apple butter.
posted by girih knot at 9:50 PM on November 10, 2012

Response by poster: Girih knot: I, too, read a lot of warnings against cooking acidic things in unlined copper pots, but I am a little confused about the matter because apparently using these sorts of pots for apple butter is pretty normal (despite apples being mildly acidic, I think).

Thanks all, for your suggestions. I think I may try intentionally scorching a little bit and giving it a taste.
posted by caaaaaam at 10:32 PM on November 10, 2012

Best answer: I've been to the apple butter making event at Mount Nebo, 962 Flintville Road, Delta, PA where they're working 7 to 10 pots each year. Debbie Beard @ 717-456-6081 usually takes the orders. She might be able to diagnose your problem or put you in touch with someone who can help.

Someone at Cornell Orchards, in your neck of the woods, might be able to help too. 607-255-4542
posted by jaimystery at 4:23 AM on November 11, 2012

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