diff --git a/src/main/java/neqsim/thermo/phase/PhaseType.java b/src/main/java/neqsim/thermo/phase/PhaseType.java
index 27991e0b56..95e69efe97 100644
--- a/src/main/java/neqsim/thermo/phase/PhaseType.java
+++ b/src/main/java/neqsim/thermo/phase/PhaseType.java
@@ -6,7 +6,6 @@
  * Types of phases.
  */
 public enum PhaseType {
-
   LIQUID("liquid", 0), GAS("gas", 1), OIL("oil", 2), AQUEOUS("aqueous", 3), HYDRATE("hydrate",
       4), WAX("wax", 5), SOLID("solid", 6), SOLIDCOMPLEX("solidComplex", 7);
 
diff --git a/src/main/java/neqsim/thermo/phase/StateOfMatter.java b/src/main/java/neqsim/thermo/phase/StateOfMatter.java
new file mode 100644
index 0000000000..777f4db24f
--- /dev/null
+++ b/src/main/java/neqsim/thermo/phase/StateOfMatter.java
@@ -0,0 +1,63 @@
+package neqsim.thermo.phase;
+
+/**
+ * States of matter, a way of relating the PhaseTypes to classical states of matter.
+ */
+public enum StateOfMatter {
+  GAS, LIQUID, SOLID;
+
+  /**
+   * Get StateOfMatter value from Phasetype object.
+   *
+   * @param pt PhaseType object
+   * @return StateOfMatter object
+   */
+  public static StateOfMatter fromPhaseType(PhaseType pt) {
+    switch (pt) {
+      case GAS:
+        return StateOfMatter.GAS;
+      case LIQUID:
+      case OIL:
+      case AQUEOUS:
+        return StateOfMatter.LIQUID;
+      case SOLID:
+      case SOLIDCOMPLEX:
+      case WAX:
+        return StateOfMatter.LIQUID;
+      default:
+        new RuntimeException(new neqsim.util.exception.InvalidInputException(StateOfMatter.class,
+            "fromPhaseType", "pt", "Conversion not configured for"));
+    }
+    return null;
+  }
+
+  /**
+   * Check if PhaseType object is a gas state of matter.
+   *
+   * @param pt PhaseType object to check.
+   * @return True if pt converts to StateOfMatter.GAS
+   */
+  public static boolean isGas(PhaseType pt) {
+    return StateOfMatter.fromPhaseType(pt) == StateOfMatter.GAS;
+  }
+
+  /**
+   * Check if PhaseType object is a liquid state of matter.
+   *
+   * @param pt PhaseType object to check.
+   * @return True if pt converts to StateOfMatter.LIQUID
+   */
+  public static boolean isLiquid(PhaseType pt) {
+    return StateOfMatter.fromPhaseType(pt) == StateOfMatter.LIQUID;
+  }
+
+  /**
+   * Check if PhaseType object is a solid state of matter.
+   *
+   * @param pt PhaseType object to check.
+   * @return True if pt converts to StateOfMatter.SOLID
+   */
+  public static boolean isSolid(PhaseType pt) {
+    return StateOfMatter.fromPhaseType(pt) == StateOfMatter.SOLID;
+  }
+}
diff --git a/src/main/java/neqsim/thermo/system/SystemThermo.java b/src/main/java/neqsim/thermo/system/SystemThermo.java
index f82105f2b8..d8e2a63074 100644
--- a/src/main/java/neqsim/thermo/system/SystemThermo.java
+++ b/src/main/java/neqsim/thermo/system/SystemThermo.java
@@ -35,6 +35,7 @@
 import neqsim.thermo.phase.PhaseSolidComplex;
 import neqsim.thermo.phase.PhaseType;
 import neqsim.thermo.phase.PhaseWax;
+import neqsim.thermo.phase.StateOfMatter;
 import neqsim.util.database.NeqSimDataBase;
 
 /*
@@ -2838,10 +2839,9 @@ public void setPhaseType(int phaseToChange, String phaseTypeName) {
     // System.out.println("new phase type: cha " + newPhaseType);
     int newPhaseType = 1;
     if (allowPhaseShift) {
-      if (phaseTypeName.equals("gas") || phaseTypeName.equals("vapour")) {
+      if (phaseTypeName.equals("gas")) {
         newPhaseType = 1;
-      } else if (phaseTypeName.equals("liquid") || phaseTypeName.equals("oil")
-          || phaseTypeName.equals("aqueous")) {
+      } else if (StateOfMatter.isLiquid(PhaseType.byDesc(phaseTypeName))) {
         newPhaseType = 0;
       } else {
         newPhaseType = 0;