Rinse rye berries and soak them in filtered water for 6-8 hours (I use a sprouting jar). If possible, keep the jar at a cooler temperature, best around 65ºF. Here is the jar I use.

Drain the water, tilt the jar to the side to let the air circulate freely, leave at cellar temperature (59-60ºF).

Rinse and drain twice a day (morning and evening) until rye starts to sprout. The amount of time it takes to sprout varies, just make sure your sprouts don't become longer than grains. I let the grains sprout a little, just to show the tails, because I don't want to deal with removing the tails.

Transfer the grains into a loosely covered glass dish, and a place that can maintain temperature of 113-122ºF (I use a 'bread proof' option on my oven and wrap the dish in foil) for 12 hours. Then I increase the temperature to 140ºF and maintain it for the next 36 hours; until solod darkens in color and has a slight malty aroma.

At this point, grain needs to dry. First I spread it thin on a large jelly-roll sheet, and leave it at 'bread-proof' temperature of my oven for 12 hours.

I then increase temperature to 159ºF and dry for 12 more hours.

One more temperature increase - 176ºF - for 12-18 hours, depending on the level of darkness I prefer at the moment.

After I cool the malt, I store it in a loosely covered jar for a month before milling it.

Now you can understand why I would much rather buy the prepared version.