Diagnosis help for Maibock

Good morning fellow beer enthusiasts,

This weekend I have been doing some homebrew sampling panels, and while the results have been generally good, there is one beer that has somehow gone way off the tracks. It is this year’s run of a Maibock. Long story short, last year’s version scored a 43/50 in a German style only homebrew competition. Unable to leave well enough alone, I altered the recipe to try and make it better and the complete opposite happened. This year’s version came out very tart with a lot of light fruity flavors, which is obviously not remotely what a Maibock should taste like.

Last year’s recipe - Pilsen LME, Crystal 20, Carapils, Hallertau and Tettnang hops, Wyeast 2124.
This year’s recipe - Pilsen & Munich LME (2:1 Pilsen to Munich), Crystal 10, Carapils, Hallertau and Tettnang hops, Wyeast 2124.

Procedures damn nearly the same for both years…beer made and cooled to around 64. Yeast pitched and taken to primary fermentation where temperature held around 52. Transferred to secondary and then put in refrigerator and held at 38 for 12 weeks last year and 8 weeks this year. Brought back to room temperature and then bottled.

Also, just for reference, I also made a Doppelbock at the same time this year that sat next to the Maibock the whole time and experienced the same conditions, and it turned out spot on.

Hoping to get some feedback on what possibly went wrong, other than I should have left the recipe alone. I cannot seem to figure out what might have caused this to go so terribly wrong. Thanks for the advice and cheers!!!

A quick BUMP for some more readers…hopefully somebody has some ideas.

Contamination? That’s what “tart and lightly fruity” makes me think.

a10t2 - I had not thought of that but I would tend to think that is not the culprit as I feel I have a very good cleaning/sanitizing routine, but I would not eliminate the possibility.

To qualify a little more, all 3 groups that tested it this weekend all like the beer and would drink it, but its just so off the mark style wise.

Thanks for the input.