In a small bowl, soak raisins in beer. Microwave on high 30 seconds. Set aside.
In a large skillet, melt butter over medium heat. Saute onion until soft and translucent, 3-5 minutes. Add diced apples and saute until apple softens, 2-3 minutes. Sprinkle with curry powder, turn heat to low, cover, and cook 8 minutes. Add ginger and cook 2 minutes longer. Sprinkle with flour and cook 1 minute until the raw taste cooks out. Drain beer into skillet, stirring continuously, then cook 5 minutes.
Add chicken stock, apple cider, cinnamon stick, bay leaf and soy sauce. Bring to a boil, then add diced sweet potato. Cook 30 minutes, or until sweet potato is tender. Remove and discard cinnamon stick and bay leaf. Process in blender, food processor or with immersion blender until smooth. Adjust seasoning with salt, pepper, and more apple cider if needed for sweetness.
Optional: for a heartier meal, add diced cooked chicken or turkey.