very very tart cider

Just racked my cider into secondary after three weeks of primary, had a little taste and its extremely tart.

I racked into another 6 gallon fermentation barrel, and i have around 5 gals of juice in it. How would i go about removing this tartness?

I still have apples on the trees around my house, however i have no idea what they are like. If i taste these, they should be very ripe, and if there sweet, can i just press these and add the sweeter juice to my secondary, and just let it ferment out again?

The sweetness in the apples i assume will still ferment out quite dry, which doesent bother me, but adding sweeter apple juice, to re-ferment, will this help remove the very very tartness?

EDIT: Also, if i add the sweeter juice, then take an og, and cold crash around 1.005, would this removes some tartness, and still leave a little bit of apple sugar?

If it is tart, but has a sour apple finish, time will usually mellow the acids and it will come around

If you want to backsweeten, I'd recommend pouring some 4oz glasses and experimenting, because the best sweetener to use depends somewhat on what is missing from the taste of what's in your keg. try cane and corn sugar, agave, fresh juice, etc, adding 1/8 tsp at a time and when you hit on something that works, then scale it up to 5 gal.

It will not take much at all. measure in 1/8 tsp of sugar or preferably less in a 4oz sample. 1/16ths are good for combining sugars. Drink or toss the samples afterwards, so you dont have to be real sanitary with these

Cane/corn sugar mix works if the juice has a decent apple taste but too thin. Agave is good if there is a big sour note but not any sweetness up front and original juice is good if not much taste at all. If you want to bottle carbonate, you need to add non fermentable sugar.

Another option would be to freeze concentrate some of it. There was a recent post that ABC was taking a more lenient approach towards freeze concentration as long as it as done for home consumption. That will concentrate the taste.

The key is not to let all of the sugar ferment out in the first place. There are different ways you can back sweeten, but nothing that I have found that replaces the last bit of apple sugar that disappears between 1.005 and 1.000

if you add the new juice and continue to ferment, it will just end up with the same level of tartness. You have to stop fermentation prior to adding the sweetner so you can balance the acids with unfermented sugars.

Also, adding straight juice really cuts down the cider. You can concentrate the juice by freezing it in milk jugs and letting the beautiful tasty sugars percipitate out by turning the jug upside down and letting it sit a while. Most of the water will be left behind as ice while the sugars and flavor will drip out into your catch container.

Well my most recent cider was really tart too, right out of the bottle. I carbed it like a beer, 4oz corn sugar to 5 gallons so its highly carbed and tart. The best thing I've found is to pour 3/4 glass of cider and top it off w/ some fresh juice. Not much, just a little right when you drink it. Obviously doing something before bottling would be easier but this has worked for me. Nice fresh apple flavor too.

A malolactic ferment reduces the acid a lot.