\begin{tikzpicture}[node distance = 3.5cm, auto]
  \node [start] (init) {Mix \qty{50}{\gram} flour + \qty{50}{\gram} water, stir};
  \node [block, right of=init] (wait2) {Wait\\ \qty{24}{\hour}};
  \path [line] (init) -- (wait2);
  \node [block, below of=wait2, node distance=3.5cm] (feed) {\qty{10}{\gram} of previous day + \qty{50}{\gram} water + \qty{50}{\gram} flour, stir};
  \path [line] (wait2) -- (feed);
  \node [block, below of=feed] (discard) {Discard the rest};
  \path [line] (feed) -- (discard);
  \node [decision, right of=feed, node distance=3.5cm] (decide) {Is good?};
  \node [decision, above of=decide, node distance=3.5cm] (timeout) {Less than 10 feeds?};
  \node [fail, right of=timeout, node distance=3.5cm] (discard2) {Batch failed};
  \path [line] (timeout) -- node{no} (discard2);
  \path [line] (timeout) -- node{yes} (wait2);
  \path [line] (feed) -- (decide);
  \node [success, right of=decide, node distance=3.5cm] (use) {Ready to use};
  \path [line] (decide) -- node{no} (timeout);
  \path [line] (wait2) -- (feed);
  \path [line] (decide) -- node{yes} (use);
\end{tikzpicture}