\begin{tikzpicture}[node distance = 3cm, auto]
  \node [block] (init) {\footnotesize Bulk fermentation};
  \node [block, right of=init] (check_dough) {\footnotesize Check the dough};
  \node [block, right of=check_dough, node distance=4cm] (size_increase) {\footnotesize Check dough size increase};
  \node [block, below of=size_increase, node distance=2cm] (ph_value) {\footnotesize Check dough pH value};
  \node [block, below of=ph_value, node distance=2cm] (smell) {\footnotesize Check dough smell};
  \node [decision, right of=ph_value, node distance=4cm] (dough_ready) {\footnotesize Dough ready?};
  \node [block, below of=dough_ready] (divide_preshape) {\footnotesize Divide and preshape};
  \node [decision, below of=smell] (dough_flattened) {\footnotesize Dough flattened out?};
  \node [block, below of=check_dough, node distance=3cm] (wait_60_minutes) {\footnotesize Wait 60~minutes};
  \node [block, below of=wait_60_minutes, node distance=4cm] (stretch_fold) {\footnotesize Stretch and fold};

  \path [line] (init) -- (check_dough);
  \path [line] (check_dough) -- (size_increase);
  \path [line] (check_dough) -- node{or} (ph_value);
  \path [line] (check_dough) -- node{or} (smell);
  \path [line] (size_increase) -- (dough_ready);
  \path [line] (ph_value) -- (dough_ready);
  \path [line] (smell) -- (dough_ready);
  \path [line] (dough_ready) -- node{yes} (divide_preshape);
  \path [line] (dough_ready) -- node{no} (dough_flattened);
  \path [line] (dough_flattened) -- node{yes} (stretch_fold);
  \path [line] (dough_flattened) -- node{no} (wait_60_minutes);
  \path [line] (stretch_fold) -- (wait_60_minutes);
  \path [line] (wait_60_minutes) -- (check_dough);
\end{tikzpicture}
