Add note on float test (#318)

The float test is not super reliable - this adds some comments on when
it can work and when it does not.

book/glossary/glossary.tex

@@ -194,6 +194,31 @@ \chapter{Glossary}%
 together. By adding the starter early the dough becomes more extensible and easier
 to handle.
 
+\item[Float test] The float test is a technique for assessing the readiness
+of a sourdough starter. To perform this test, take a small sample of
+your starter and gently place it in a glass of water. The outcome
+of this test can provide insights into your starter's fermentation stage.
+
+\begin{itemize}
+\item[] \emph{Positive result:} If your starter effortlessly floats on the
+surface of the water, it's a clear indication that it has reached its peak
+of fermentation and is ready to be used as a leavening agent in your dough.
+This buoyancy is a result of the carbon dioxide gas produced during
+the active fermentation process.
+\item[] \emph{Negative result:} Conversely, if your starter sinks to the
+bottom of the glass, it suggests that it's not quite ready yet.
+This indicates that the fermentation process has not progressed
+sufficiently for optimal leavening power.
+\end{itemize}
+
+It's worth noting that while the float test is a reliable indicator
+for wheat-based sourdough starters, it may not be as effective for non-wheat
+starters. This is because the gas generated during fermentation in non-wheat
+starters tends to escape more readily, making it less buoyant. For non-wheat
+starters, a more accurate approach involves observing the presence of
+bubbles in your starter jar and assessing its aroma. A mature starter should
+emit a mildly sour, but not overly pungent, scent.
+
 \item[Fool’s Crumb] A term used to describe a crumb structure that has several
 large pockets or holes, rather than an even distribution of smaller holes. This
 isn't necessarily a desired feature, as it can indicate uneven fermentation or

book/troubleshooting/misc.tex

@@ -345,6 +345,17 @@ \subsection{Why does my starter smell like vinegar or acetone?}
 is incredible. It nicely plays with soups as well. Just take
 a bit of this bread and dip it in your soup.
 
+\subsection{Why does my starter not float after using the float test?}
+The float test may not reliably determine your starter's readiness for dough
+inoculation. While it's effective for wheat-based doughs, where ample gas gets
+trapped in the gluten matrix, it's less reliable for non-wheat doughs. In non-
+wheat doughs, the gas generated during fermentation tends to escape, causing
+the starter to likely sink.
+
+For more accurate assessments of your starter's readiness, watch for bubbles
+at the container's edge and consider its aroma. A mature starter should emit a
+mildly sour scent without being overly pungent.
+
 \section{Dough}
 \subsection{Should I~autolyse my dough?}