\begin{tikzpicture}[node distance = 3cm, auto]
  \node [start] (init) {Make a starter};
  \node [block, right of=init, node distance=3cm] (feed) {Feed your starter};
  \path [line] (init) -- (feed);
  \node [block, right of=feed, node distance=3cm] (wait_12_after_feed) {Wait\\ \qty{12}{\hour}};
  \path [line] (feed) -- (wait_12_after_feed);
  \node [block, right of=wait_12_after_feed, node distance=3cm] (ready_question) {Perform readiness check};
  \path [line] (wait_12_after_feed) -- (ready_question);
  \node [block, above of=feed, node distance=3cm] (wait_12) {Wait\\ \qty{12}{\hour}};
  \path [line] (wait_12) -- (feed);
  \node [decision, right of=ready_question, node distance=3.2cm] (is_bubbly) {Bubbly? Size Increase?};
  \path [line] (ready_question) -- (is_bubbly);
  \path [line] (is_bubbly) -- node[anchor=east, above=2pt] {no} ++(2.2,0) |- (wait_12);
  \node [decision, below of=is_bubbly, node distance=4.0cm] (check_smell) {Vinegary, or yogurt smell?};
  \path [line] (is_bubbly) -- node{yes} (check_smell);
  \node [success, below of=wait_12_after_feed, node distance=4cm] (make_dough) {Make your dough};
  \path [line] (check_smell) -- node[anchor=west, above=2pt]{yes} (make_dough);
  \path [line] (check_smell) -- node[anchor=east, above=2pt] {no} ++(2.2,0) |- (wait_12);
\end{tikzpicture}