diff --git a/src/main/java/de/ids_mannheim/korap/KrillCollection.java b/src/main/java/de/ids_mannheim/korap/KrillCollection.java
index 19f06ae..e408dfc 100644
--- a/src/main/java/de/ids_mannheim/korap/KrillCollection.java
+++ b/src/main/java/de/ids_mannheim/korap/KrillCollection.java
@@ -1,11 +1,14 @@
 package de.ids_mannheim.korap;
 
+import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.io.IOUtils;
 import org.apache.lucene.index.DocsAndPositionsEnum;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -91,22 +94,6 @@
         this.index = index;
     };
 
-
-    /**
-     * Constructs a KrillCollection according to the given KrillIndex
-     * and KoralQuery.
-     * 
-     * KrillIndex is necessary for caching virtual corpora.
-     * 
-     * @param index
-     * @param jsonString
-     */
-    public KrillCollection (KrillIndex index, String jsonString) {
-        this.index = index;
-        createCollection(jsonString);
-    };
-
-
     /**
      * Construct a new KrillCollection by passing a KoralQuery.
      * 
@@ -397,9 +384,26 @@
 
             Element element = cache.get(ref);
             if (element == null) {
-                this.addError(StatusCodes.MISSING_COLLECTION,
-                        "Collection is not found.");
-                return this.build().nothing();
+                String corpusQuery = loadVCFile(ref);
+                if (corpusQuery == null){
+                    return this.build().nothing();
+                }
+                else{
+                    JsonNode node;
+                    try {
+                        node = mapper.readTree(corpusQuery);
+                    }
+                    catch (IOException e) {
+                        throw new QueryException(StatusCodes.INVALID_QUERY, 
+                                "Failed parsing collection query to JsonNode.");
+                    }
+                    if (!node.has("collection")){
+                        this.addError(StatusCodes.MISSING_COLLECTION,
+                                "KoralQuery does not contain a collection.");
+                        return this.build().nothing();
+                    }
+                    return cb.toCacheVC(ref, this._fromKoral(node.at("/collection")));
+                }
             }
             else {
                 CachedVCData cc = (CachedVCData) element.getObjectValue();
@@ -412,6 +416,20 @@
         throw new QueryException(813, "Collection type is not supported");
     };
 
+    
+    private String loadVCFile (String ref) {
+        File file = new File(ref);
+        String json = null;
+        try {
+            FileInputStream fis = new FileInputStream(file);
+            json = IOUtils.toString(fis);
+        }
+        catch (IOException e) {
+            this.addError(StatusCodes.MISSING_COLLECTION,
+                    "Collection is not found.");
+        }
+        return json;
+    }
 
     /**
      * Set the collection from a {@link CollectionBuilder} object.
@@ -798,7 +816,7 @@
         this.cbi = cb.namedVC(cc);
         return cc;
     }
-
+    
     public String getName () {
         return name;
     }
diff --git a/src/main/java/de/ids_mannheim/korap/collection/CollectionBuilder.java b/src/main/java/de/ids_mannheim/korap/collection/CollectionBuilder.java
index b3ee552..5705f14 100644
--- a/src/main/java/de/ids_mannheim/korap/collection/CollectionBuilder.java
+++ b/src/main/java/de/ids_mannheim/korap/collection/CollectionBuilder.java
@@ -2,10 +2,13 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.Iterator;
+import java.util.Map;
 
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.queries.TermsFilter;
+import org.apache.lucene.search.DocIdSet;
 import org.apache.lucene.search.Filter;
 import org.apache.lucene.search.NumericRangeFilter;
 import org.apache.lucene.search.PhraseQuery;
@@ -399,8 +402,47 @@
         }
         
     }
+    
+    /** Wraps a sub CollectionBuilder.Interface to allows VC caching
+     *  
+     * @author margaretha
+     *
+     */
+    public class ToCacheVC implements CollectionBuilder.Interface {
 
+        private CollectionBuilder.Interface child;
+        private String cacheKey;
+        
+        private Map<Integer, DocIdSet> docIdMap;
+
+        public ToCacheVC (String vcRef, Interface cbi) {
+            this.child = cbi;
+            this.cacheKey = vcRef;
+            this.docIdMap  = new HashMap<Integer, DocIdSet>();
+        }
+
+        @Override
+        public Filter toFilter () {
+            return new ToCacheVCFilter(cacheKey,docIdMap, child, child.toFilter());
+        }
+
+        @Override
+        public boolean isNegative () {
+            return child.isNegative();
+        }
+
+        @Override
+        public CollectionBuilder.Interface not () {
+            // not supported
+            return this;
+        }
+    }
+    
     public Interface namedVC (CachedVCData cc) {
         return new CollectionBuilder.CachedVC(cc);
     }
+    
+    public Interface toCacheVC (String vcRef, Interface cbi) {
+        return new CollectionBuilder.ToCacheVC(vcRef, cbi);
+    }
 };
diff --git a/src/main/java/de/ids_mannheim/korap/collection/ToCacheVCFilter.java b/src/main/java/de/ids_mannheim/korap/collection/ToCacheVCFilter.java
new file mode 100644
index 0000000..2928de3
--- /dev/null
+++ b/src/main/java/de/ids_mannheim/korap/collection/ToCacheVCFilter.java
@@ -0,0 +1,63 @@
+package de.ids_mannheim.korap.collection;
+
+import java.io.IOException;
+import java.util.Map;
+
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.DocIdSet;
+import org.apache.lucene.search.Filter;
+import org.apache.lucene.util.Bits;
+import org.apache.lucene.util.FixedBitSet;
+
+import de.ids_mannheim.korap.KrillCollection;
+import de.ids_mannheim.korap.collection.CollectionBuilder.Interface;
+import net.sf.ehcache.Element;
+
+public class ToCacheVCFilter extends Filter {
+
+
+    private Filter filter;
+    private CollectionBuilder.Interface cbi;
+    private String cacheKey;
+    private Map<Integer, DocIdSet> docIdMap;
+
+    public ToCacheVCFilter (String cacheKey, Map<Integer, DocIdSet> docIdMap,
+                            Interface cbi, Filter filter) {
+        this.cacheKey = cacheKey;
+        this.docIdMap = docIdMap;
+        this.cbi = cbi;
+        this.filter = filter;
+    }
+
+    @Override
+    public DocIdSet getDocIdSet (LeafReaderContext context, Bits acceptDocs)
+            throws IOException {
+
+        DocIdSet docIdSet = filter.getDocIdSet(context, acceptDocs);
+
+        final LeafReader reader = context.reader();
+        int maxDoc = reader.maxDoc();
+        FixedBitSet bitset = new FixedBitSet(maxDoc);
+
+        if (docIdSet == null) {
+            if (this.cbi != null) {
+                bitset.clear(0, bitset.length());
+            }
+            else {
+                bitset.set(0, bitset.length());
+            };
+        }
+        else {
+            bitset.or(docIdSet.iterator());
+        }
+
+        docIdMap.put(context.hashCode(), new SerializableDocIdSet(bitset));
+        CachedVCData cachedVCData = new CachedVCData(docIdMap);
+
+        KrillCollection.cache.put(new Element(cacheKey, cachedVCData));
+
+        return docIdSet;
+    }
+
+}
diff --git a/src/main/java/de/ids_mannheim/korap/response/Notifications.java b/src/main/java/de/ids_mannheim/korap/response/Notifications.java
index 877c655..722dc6e 100644
--- a/src/main/java/de/ids_mannheim/korap/response/Notifications.java
+++ b/src/main/java/de/ids_mannheim/korap/response/Notifications.java
@@ -46,7 +46,7 @@
 public class Notifications {
 
     // Create object mapper for JSON generation
-    ObjectMapper mapper = new ObjectMapper();
+    protected ObjectMapper mapper = new ObjectMapper();
 
     private Messages warnings, errors, messages;
 
diff --git a/src/main/resources/ehcache.xml b/src/main/resources/ehcache.xml
index 0cb69b7..00465bf 100644
--- a/src/main/resources/ehcache.xml
+++ b/src/main/resources/ehcache.xml
@@ -1,4 +1,4 @@
-<ehcache xsi:noNamespaceSchemaLocation="ehcache.xsd"
+<ehcache xsi:noNamespaceSchemaLocation="http://www.ehcache.org/ehcache.xsd"
 	updateCheck="true" monitoring="autodetect" dynamicConfig="true">
 
 	<diskStore path="./krill_cache" />
@@ -10,11 +10,12 @@
 		timeToLiveSeconds="1200">
 	</defaultCache>
 
-	<cache name='named_vc' 
-		eternal='true' 
+	<cache name="named_vc" 
+		eternal="true" 
 		memoryStoreEvictionPolicy="LRU" 
-		maxBytesLocalHeap="256M"
-		maxBytesLocalDisk="1G"
-		overflowToDisk='true' />
+		maxBytesLocalHeap="256M" >
+		<!-- maxBytesLocalDisk="1G"> 
+		<persistence strategy="localTempSwap"/> -->
+	</cache>
 
 </ehcache>
\ No newline at end of file