I suspect you're probably right.
The Boskoop is known for being able to store all winter long (and flavor actually gets better in storage).
And given the preservative qualities of vitamin C, that would make sense.

another apple known for it's vitamin c content is calville blanc. I has boscoop for the first time off my tree and they are quite acidic. When the brix peaks, the combination sweet and acidic is really yummy.

Thank you all!

Axel, thanks... I was reading this yesterday too, the Calville Blanc is at around 18 mg /100gr, some others I found today.

30 - 35 mg in Braeburn
25 mg in Sturmer
15 - 20 mg in Idared
16.... in Ribston
15.....in Blenheim

Boskoop I used to pick thousend of pounds, back in Switzerland when I was a teen.
I loved this apple the most for picking, lovely looking with red cheeks, late apple, huge sturdy trees.
But I don't think I have eaten more than five apples fresh,.. too sour!
We stored some, execllent keepers and one of the best cooking apples.
Actually, I had a graft on one of my trees here and had some apples on for two seasons,
fireblight got into this tree and choped it down, but forgot to keep some scion wood.
Hopefully I can get it back.

Konrad

Konrad, should be easy to order, or to get scion wood, I can send you some this Winter if you like. My tree is certified disease free as of right now.

Boscoop is too sour to eat fresh when they're picked like they're supposed to - that is before they are fully ripe. I had a tree ripened apple that I thought was out of this world. And I hear they're best when stored until about December. Then they mellow to a good eating apple.

I had no idea Braeburn has 30mg. I can vouch that store bought braeburns don't have that much vitamin c, and they taste terrible. Home grown, tree ripened braeburns are most amazing.

I read somewhere,that Antonovka has the highest vitamine C of all apples. It is sure sour before it is fully ripe.
Olga

Calville tastes like an orange to me, cerealiously.
Braeburn tastes nothing like an orange. I wonder if this is one of those Internet rumours.

Thank you all!
Axel, thank you for your offer!
Perhaps I can get it local, from the place I got it before, the fellow past on, the wife might be able to help me out?

Olga, Some of my trees are on Antonovka rootstock, I didn't know until today, that it produces large apple.
Your post make me want to grow a tree, this one makes good apple wine too, it's good to have some tart apples
around for blending.

Geraldo,
Interesting, I don't grow any of these.
Some Websites say, that Calville has more Vitamin C then Oranges, ....... this is FALSE!
Oranges run around 60 mg.

Konrad

Antonovka is the best for apple pies too, in my opinion. I don't have space for big apple tree now, but I miss it more then any other fruit trees.
Olga

My best apple for pies up here north is the Collet, so far, nothing beats this one, everybody is raving about this
pie!

{{gwi:125521}}
{{gwi:125522}}
..

The flesh is nice and white
{{gwi:125523}}
..
Konrad

I think Northern Spy has close to 50mg, but I can not find where I read about it. it did say that corresponds to about ten times the average apple content. It is a very unusual apple, a truly wild one (discovered in NY state in the 1840s and propagated from a single tree), huge trees that stay productive for decades (some for 100 years).
It is also the rare one that has good eating, keeping, baking, and cider quality (at least here in MI).

No reason why some apples should not have large amounts of Vit. C, since they are in the rosaceae family and rose hips are mega sources, but the reality is that on average, apples are poor Vit. C contributors to one's diet.