Sunday, August 5, 2012

Triple-decoction vs. No-sparge + melanoidin malt.

I don't blog much anymore because I don't have a lot of free time, and I've decided I don't like posting low-quality content. I think this post might be interesting to some people, so I'm putting it out there.

This study was really easy to put together, very hard to analyze. I'm providing my data so you can look at it for yourself to decide if I draw a reasonable conclusion. If you disagree with my methods or results, it's easy to find qualified people on the AHA forum to serve as evaluators. Any study is useless if it can't be replicated, so I encourage anyone interested in this topic to organize their own study.

Latest version of results and summary.
Pre-taste questionnaire
Post-taste questionnaire
BJCP scoresheets

3X on the left, 5% on the right, chill haze on both.
Big picture (my conjecture based on this study and everything I know about brewing):
1) Decoction probably won't make your beer better.
2) Decoction mashing extracts more gravity from malt, and it probably extracts more compounds that can be perceived as "dry" as well. Whether that's good or bad for a given recipe will depend on personal preference and your targeted beer profile.
3) Using melanoidin malt doesn't emulate decoction mashing
4) There were a lot of contradictory descriptions of the beers. How people perceive aroma and flavor is complex and not easy to anticipate.

What the data supports:
1) Decoction increases mash efficiency.
2) There was no statistically significant correlation between the BJCP scores and recipe.
3) 57% of evaluators preferred the no-sparge beer with 5% melanoidin malt (5%) over the triple-decocted beer (3X), 29% had no preference, and 14% preferred 3X.
4) Judges were significantly more likely to correctly identify duplicate beers than expected based on a random guess.

What the data probably supports:
1) Small difference with 3X leaning toward dry/bitter, 5% leaning toward malty/balanced.

What the data might support:
1) No difference other than color
2) Small difference, but no agreed-upon difference.
3) Either no-sparge or decoction had no effect, and the only difference was due to melanoidin malt, or vice versa.

What the data doesn't support:
1) Decoction makes a better beer
2) Decoction makes your beer maltier than using melanoidin malt w/no sparge.
3) Decoction makes a smoother beer
4) Decoction makes a beer more people prefer

Problems with the study:
1) Small sample size
2) I only have room for two fermentors in my freezer, so I could only make two beers at once to compare. I could've made smaller batches, but I wanted them to be "typical" homebrew batch sizes.
3) There were some issues with inconsistent carbonation from bottle priming. I've never noticed a difference in carbonation levels in my beer before, so this was really interesting for me.
4) A couple samples may have had a low-level infection. If I could consistently brew perfect beer, I wouldn't spend so much time on the internet trying to learn about brewing.
5) Mixed variables: I framed the study as a comparison of no-sparge vs decoction because I wanted to confound evaluators' expectations. If decoction could provide some special je ne sai quoi beyond just darker color and increased maltiness in a way that melanoidin malt can't emulate, that should have shown up in the results, with more people preferring 3X or more people describing 3X in more favorable terms. In any case, it's possible the no-sparge, decoction or the melanoidin malt had no effect, but I'd say it's more likely that no-sparge or decoction had no effect and melanoidin malt had some effect.

1 comment:

  1. Wow, this is fantastic. I read so much opinion on the forums but there is so little evidence to back any of it up.

    I've done decoction in the past and it was a pain on my equipment. I was thinking of doing it again on my next brew to follow the recipe for Berliner Weisse in the Mad Fermentationist's book but I think I'll skip it after all. I know I can do a single infusion even with a sparge in a relatively short amount of time and without hiccups. This means I'll be able to brew sooner than if I did the more lengthy decoction method. That is more important to me than a minor difference in taste that may or may not even be noticeable in the end.

    Keep up the excellent work!


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