diff --git a/FIAT/reference_element.py b/FIAT/reference_element.py
index 0dcb5825e..a34b444ee 100644
--- a/FIAT/reference_element.py
+++ b/FIAT/reference_element.py
@@ -38,6 +38,7 @@
 QUADRILATERAL = 11
 HEXAHEDRON = 111
 TENSORPRODUCT = 99
+_family_cache = {}
 
 
 def multiindex_equal(d, isum, imin=0):
@@ -77,7 +78,11 @@ def make_lattice(verts, n, interior=0, family="equi"):
     and interior = 0, this function will return the vertices and
     midpoint, but with interior = 1, it will only return the
     midpoint."""
-    family = _decode_family(family)
+    key = family
+    try:
+        family = _family_cache[key]
+    except KeyError:
+        family = _family_cache.setdefault(key, _decode_family(family))
     D = len(verts)
     X = numpy.array(verts)
     get_point = lambda alpha: tuple(numpy.dot(_recursive(D - 1, n, alpha, family), X))