Have commodity prices bottomed? I think this is a great question and I am certainly not the first to write about it. The Fed probably asks this question at every meeting. Bond gurus like Bill Gross and Jeff Gundlach probably ask the question. Mario Draghi asks it in Italian.
All measures of commodity prices are flawed. None of them does it right but everyone has their favorite measure. I like to use the CRB index or when I learned about it in the early 1970's it was the Commodity Research Bureau Index. Keeping that in mind lets look at two charts.
In this weekly bar chart of the CRB, below, we can see a long decline from early 2015 to early 2016. The index bases from 2016 to the end of 2017. Now we can see a breakout from this base pattern with the index above the rising 40-week moving average line. The trend-following Moving Average Convergence Divergence (MACD) oscillator crossed above the zero line in November and continues upwards in a bullish mode. Is it oil prices? Is it the weak dollar? Is the lack of investment in new mines? Is is increased demand pushing against limited supplies? As a technical analyst I do not worry too much about the causes as I try to focus on the effects.

In this Point and Figure chart of the CRB, below, we can see the breakout at 198. A 225 target is shown.
Bottom line: The cost of materials is just one part of whether there is inflation. Labor and marketing are also a big part of the picture. With the U.S. labor market becoming tight, according to some analysts, bond traders and others need to watch commodity prices even closer.