diff --git a/py/rvspecfit/make_ccf.py b/py/rvspecfit/make_ccf.py
index b0f199b..d182d03 100644
--- a/py/rvspecfit/make_ccf.py
+++ b/py/rvspecfit/make_ccf.py
@@ -188,7 +188,12 @@ def preprocess_model(logl, lammodel, model0, vsini=None, ccfconf=None):
     return c_model
 
 
-def preprocess_model_list(lammodels, models, params, ccfconf, vsinis=None):
+def preprocess_model_list(lammodels,
+                          models,
+                          params,
+                          ccfconf,
+                          vsinis=None,
+                          nthreads=1):
     """Apply preprocessing to the array of models
 
     Parameters
@@ -218,29 +223,35 @@ def preprocess_model_list(lammodels, models, params, ccfconf, vsinis=None):
          3) spectral params
          4) list of vsini
     """
-    nthreads = 16
     logl = np.linspace(ccfconf.logl0, ccfconf.logl1, ccfconf.npoints)
     res = []
     retparams = []
     if vsinis is None:
         vsinis = [None]
     vsinisList = []
-    pool = mp.Pool(nthreads)
+    if nthreads > 1:
+        pool = mp.Pool(nthreads)
     q = []
     for imodel, m0 in enumerate(models):
         for vsini in vsinis:
             retparams.append(params[imodel])
-            q.append(
-                pool.apply_async(preprocess_model,
-                                 (logl, lammodels, m0, vsini, ccfconf)))
+            curargs = (logl, lammodels, m0, vsini, ccfconf)
+            if nthreads > 1:
+                q.append(pool.apply_async(preprocess_model, curargs))
+            else:
+                q.append(preprocess_model(*curargs))
             vsinisList.append(vsini)
 
     for ii, curx in enumerate(q):
         print('Processing : %d / %d' % (ii, len(q)))
-        c_model = curx.get()
+        if nthreads > 1:
+            c_model = curx.get()
+        else:
+            c_model = curx
         res.append(c_model)
-    pool.close()
-    pool.join()
+    if nthreads > 1:
+        pool.close()
+        pool.join()
     retparams = np.array(retparams)
     vsinisList = np.array(vsinisList)
     res = np.array(res)
@@ -379,7 +390,8 @@ def ccf_executor(spec_setup,
                  oprefix=None,
                  every=10,
                  vsinis=None,
-                 revision=''):
+                 revision='',
+                 nthreads=1):
     """
     Prepare the FFT transformations for the CCF
 
@@ -429,7 +441,8 @@ def ccf_executor(spec_setup,
                                                    specs,
                                                    vec,
                                                    ccfconf,
-                                                   vsinis=vsinis)
+                                                   vsinis=vsinis,
+                                                   nthreads=nthreads)
     ffts = np.array([np.fft.rfft(x) for x in models])
     fft2s = np.array([np.fft.rfft(x**2) for x in models])
     savefile = (oprefix + '/' +
@@ -479,6 +492,10 @@ def main(args):
                         help='Wavelength endpoint',
                         required=True)
 
+    parser.add_argument('--nthreads',
+                        type=int,
+                        help='Number of threads',
+                        default=8)
     parser.add_argument('--nocontinuum',
                         dest='nocontinuum',
                         action='store_true')
@@ -525,7 +542,8 @@ def main(args):
                  args.oprefix,
                  args.every,
                  vsinis,
-                 revision=args.revision)
+                 revision=args.revision,
+                 nthreads=args.nthreads)
 
 
 if __name__ == '__main__':
diff --git a/tests/make_templ.sh b/tests/make_templ.sh
index ba07fff..abdf5de 100755
--- a/tests/make_templ.sh
+++ b/tests/make_templ.sh
@@ -23,4 +23,4 @@ $RVS_MAKE_INTERPOL --air --setup $BNAME --lambda0 $BLAM0 --lambda1 $BLAM1 --reso
 
 $RVS_MAKE_ND --prefix ${PREFIX}/ --setup $BNAME
 
-$RVS_MAKE_CCF --setup $BNAME --lambda0 $BLAM0 --lambda1 $BLAM1  --every 3 --vsinis $VSINIS --prefix ${PREFIX}/ --oprefix=${PREFIX} --step $BSTEP
+$RVS_MAKE_CCF --nthreads 1 --setup $BNAME --lambda0 $BLAM0 --lambda1 $BLAM1  --every 3 --vsinis $VSINIS --prefix ${PREFIX}/ --oprefix=${PREFIX} --step $BSTEP