diff --git a/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/system/NBEnvironment.java b/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/system/NBEnvironment.java
index 092430fe3..712446faa 100644
--- a/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/system/NBEnvironment.java
+++ b/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/system/NBEnvironment.java
@@ -217,7 +217,7 @@ public class NBEnvironment {
      * @return The interpolated value, after substitutions, or null if any lookup failed
      */
     public Optional<String> interpolate(String word, Map<String,String> supplemental) {
-        Pattern envpattern = Pattern.compile("\\$(?<env1>[a-zA-Z_][A-Za-z0-9_.]+)|\\$\\{(?<env2>[a-zA-Z_][A-Za-z0-9_.]*)(:(?<default>[a-zA-Z0-9_.]+))?\\}");
+        Pattern envpattern = Pattern.compile("\\$(?<env1>[a-zA-Z_][A-Za-z0-9_.]+)|\\$\\{(?<env2>[a-zA-Z_][A-Za-z0-9_.]*)(:(?<default>[a-zA-Z0-9_./\\- ]+))?\\}");
         Matcher matcher = envpattern.matcher(word);
         StringBuilder sb = new StringBuilder();
         while (matcher.find()) {