diff --git a/definitions/grib2/parameters.def b/definitions/grib2/parameters.def
index 56320917e..8c63b8db8 100644
--- a/definitions/grib2/parameters.def
+++ b/definitions/grib2/parameters.def
@@ -33,7 +33,7 @@ if (tablesVersion >= 31 ) {
   concept chemShortName (unknown,"chemShortName.def",conceptsDir2,conceptsDir1): no_copy,dump;
   concept chemFormula (unknown,"chemFormula.def",conceptsDir2,conceptsDir1): no_copy,dump;
 
-  if ( !(chemId is minus_one) ) {
+  if ( chemId != -1 ) {
     alias mars.chem = chemId;
     alias parameter.chemId = chemId;
     alias ls.chemShortName = chemShortName;
@@ -47,7 +47,7 @@ if (tablesVersion >= 31 ) {
   concept srcSinkName (unknown,"srcSinkName.def",conceptsDir2,conceptsDir1): no_copy,dump;
   concept srcSinkShortName (unknown,"srcSinkShortName.def",conceptsDir2,conceptsDir1): no_copy,dump;
 
- if ( !(srcSinkId is minus_one) ) {
+ if ( srcSinkId != -1 ) {
   alias mars.srcSink = srcSinkId;
   alias parameter.srcSinkId = srcSinkId;
   alias ls.srcSinkShortName = srcSinkShortName;