This recipe isn't exactly formal because much of it will depend upon the apple cider you use and the beach plum juice; I'd expect variations in alcohol content according to sugar content in juice and the ripeness of the beach plums.
-4 gallons of local cider
-1 gallon of beach plum juice.
-1 packet of preferred yeast (I used ale yeast which turned out a bit better than most of the champagne yeasts I have used prior)
-Pectic enzyme (to ensure clarity)
-12 oz of honey (if you'd like to strengthen the cider)
-Dextrose for botttling
Notes on ingredients;
-Local should mean that it isn't bottled with potassium sorbate which will prevent the yeast from converting sugar into alcohol. If you can't find unpasteurized/unpreserved cider be you can introduce a yeast bomb to the cider which has worked every time I have tried it, just try to buy local stuff because it will have less contaminants most of the time.
-Beach plums aren't exactly a widely available fruit. As I live along the water and the summer was quite hot it was a record yield. Beach plums were harvested from the tree when ripe and sorted through to get rid of any of the rotten/spoiled fruit. The fruit was put in a pot with water to cover just over three inches of the fruit. When the water reached a boil the fruit was mashed to dissolve sugars into the water and remove pits from pulp. The juice and mash were then put through a colander and sieve to remove pulp and unwanted goodies. Excess juice can be used to turn into jam rather easily.
-You can use really whatever yeast you'd like. This was my first time using ale yeast for cider (rather than a champagne) and I quite like the difference.
Pasteurize the cider through a quick boil. You need to kill off any bacteria or wild yeasts that you may fear will contaminate the flavor. I don't normally do this unless I have juiced the apples or the cider is truly all natural (sans potassium sorbate). It should be noted though that the natural yeasts (spontaneous fermentation) can yield very good results if you'd like to experiment, however you risk bacterial presence.
You can just add this to the primary while you wait for the yeast bomb to kick off, just keep it well sealed and contaminant free.
Pasteurize the beach plum juice as well. Add honey if desired (especially if you are going to need this as a yeast starter).
If you need to use a yeast bomb, add the yeast to the beach plum/honey mixture when it is lukewarm and allow it to go bananas. I use water jugs for this, and don't add the starter until it is visually bubbling more than a soda/soda water. This can take anywhere from 3 hours to 8; don't add this prematurely.
Combine your beach plum juice with cider and yeast. Add pectic enzyme (2.5 tsp, or .5 tsp per gallon of juice if you are varying batch size).
Let the fermentation take it's course. I found that the ale yeast ferments a bit less violently than the champagne yeasts I have used, so just keep an eye on it and take a measurement to ensure fermentation is complete.
Dextrose; I add more than 3/4 of a cup but less than a cup because I like mine a bit fizzier. Bottle it up and wait at least a week. I have some stored away and expect it will actually get better over a time (as per most ciders).
The color is a beautiful ruby red (I need to upload pictures to share) but it is one of the more brilliant reds I have ever seen, and more impressively it's largely all natural. I was afraid the bitterness of beach plums would show through and make this a batch I wouldn't forget nor make again, but beyond simple novelty this is my favorite I have made. It tastes more of a Cantillon lambic than anything else.