diff --git a/src/cfa_config_generator/utils/epinow2/constants.py b/src/cfa_config_generator/utils/epinow2/constants.py
index dfa4c15..41e7db6 100644
--- a/src/cfa_config_generator/utils/epinow2/constants.py
+++ b/src/cfa_config_generator/utils/epinow2/constants.py
@@ -3,6 +3,7 @@
     "horizon": 14,
     "priors": {"rt": {"mean": 1.0, "sd": 0.2}, "gp": {"alpha_sd": 0.01}},
     "sampler_opts": {
+        "backend": "rstan",
         "cores": 4,
         "chains": 4,
         "iter_warmup": 5000,