diff --git a/src/ast/rewriter/poly_rewriter_def.h b/src/ast/rewriter/poly_rewriter_def.h
index d65960857..25535856e 100644
--- a/src/ast/rewriter/poly_rewriter_def.h
+++ b/src/ast/rewriter/poly_rewriter_def.h
@@ -346,14 +346,16 @@ br_status poly_rewriter<Config>::mk_nflat_mul_core(unsigned num_args, expr * con
             SASSERT(sums.back()[0] == arg);
         }
     }
+    unsigned orig_size = sums.size();
     expr_ref_buffer sum(m()); // must be ref_buffer because we may throw an exception
     ptr_buffer<expr> m_args;
     TRACE("som", tout << "starting som...\n";);
     do {
         TRACE("som", for (unsigned i = 0; i < it.size(); i++) tout << it[i] << " ";
               tout << "\n";);
-        if (sum.size() > m_som_blowup)
-            throw rewriter_exception("sum of monomials blowup");
+        if (sum.size() > m_som_blowup * orig_size) {
+            return BR_FAILED;
+        }
         m_args.reset();
         for (unsigned i = 0; i < num_args; i++) {
             expr * const * v = sums[i];
diff --git a/src/ast/rewriter/poly_rewriter_params.pyg b/src/ast/rewriter/poly_rewriter_params.pyg
index 18d1e1dba..7e909d4aa 100644
--- a/src/ast/rewriter/poly_rewriter_params.pyg
+++ b/src/ast/rewriter/poly_rewriter_params.pyg
@@ -2,7 +2,7 @@ def_module_params(module_name='rewriter',
                   class_name='poly_rewriter_params',
                   export=True,
                   params=(("som", BOOL, False, "put polynomials in som-of-monomials form"),
-                          ("som_blowup", UINT, UINT_MAX, "maximum number of monomials generated when putting a polynomial in sum-of-monomials normal form"),
+                          ("som_blowup", UINT, 10, "maximum increase of monomials generated when putting a polynomial in sum-of-monomials normal form"),
                           ("hoist_mul", BOOL, False, "hoist multiplication over summation to minimize number of multiplications"),
                           ("hoist_cmul", BOOL, False, "hoist constant multiplication over summation to minimize number of multiplications"),
                           ("flat", BOOL, True, "create nary applications for and,or,+,*,bvadd,bvmul,bvand,bvor,bvxor")))