diff --git a/src/packer/core.clj b/src/packer/core.clj
index ff7db21..1d561b8 100644
--- a/src/packer/core.clj
+++ b/src/packer/core.clj
@@ -30,10 +30,22 @@
       "\n"
       (produce-items items nights i18n))))
 
+(defn validate-profile [store profile]
+  (let [all-items     (->> store
+                           vals
+                           flatten
+                           (map :key))
+        missing-items      (remove (set all-items) profile)
+        missing-items-str  (clojure.string/join ", " missing-items)]
+  (when (not (empty? missing-items))
+    (throw (Exception. (str "The following keys are found in the profile, but they are not defined in store: " missing-items-str))))))
+
 (defn produce [store profile nights i18n]
-  (->> store
-      keys
-      (map (fn [category] [category (filter #(.contains profile (:key %)) (get store category))]))
-      (filter #(not (empty? (second %))))
-      (map #(produce-category (first %) (second %) nights i18n))
-      (clojure.string/join "\n\n")))
\ No newline at end of file
+  (do
+    (validate-profile store profile)
+    (->> store
+        keys
+        (map (fn [category] [category (filter #(.contains profile (:key %)) (get store category))]))
+        (filter #(not (empty? (second %))))
+        (map #(produce-category (first %) (second %) nights i18n))
+        (clojure.string/join "\n\n"))))
\ No newline at end of file