"Memorial Wheat berries" (but, I did sorta just make that up, trying to translate), is called different things in different cultures. Kohliva, is the way most Americans spell it and say it. Russians, Greek, Serbian, Ukrainian, etc. etc. each spell it a little differently, but it is basically the same thing.
Christ mentions how the grain of wheat must die in order to bring forth new life, and this is why most Kohliva is made with wheat berries. It doesn't have to be though. The Japanese always use rice, because that is their main food staple. Some Russians use rice because of a famine many years back, where no one could find and wheat, but they were able somehow to find some rice, and so some still use the rice since it has become traditional.
Anyway...you cook the wheat berries, remembering that we must all die in order to bring new life, and we must die in this life in order to be born anew in the new life to come. The berries are cooked until they just barely start to soften and split, but stop before they get mushy.
Then you need to drain them very well, and then lay them out on paper towels and clean kitchen towels to dry totally (if you are making Russian or Greek Kohliva, the Serbians like the berries wetter).
Once the berries are the way you want them according to your tradition, you add 'other stuff'. The 'other stuff' also varies according to tradition, but must have sweet for the joy of your loved one going to be with Christ, as well as bitter for the sadness that we can no longer be with our loved one.
I love Almonds for their both bitter and sweet. The Arabs always use lots of anise, but I don't like that, so I don't use that. Anyway, other possible 'other stuff' varies greatly by tradition of course:
orange peal
parsley (also used for the green of the earth from which we are made)
pomegranate seeds (also to show the blood of Christ)
chocolate
plum brandy (I think only the Serbs use this)
sesame seeds
lots of other possibles too.
I should mention, this is all Orthodox Christian. We do the memorial service once a year, on the anniversary of the death. The first year they are dead though, there is of course the funeral, then a memorial service I *think* at 1 month, 3 months, 6 months, 9 months, and then after that just once a year. I am in a tiny parish, it has been awhile since someone has died.