Crushed grain longevity experiment

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

pjj2ba

Look under the recliner
HBT Supporter
Joined
Jul 25, 2006
Messages
3,372
Reaction score
235
Location
State College
I helped my wife set up and run a new lab for her class (Intro. Plant Biology) that primarily was to show the students starch conversion. She used to have them do this complicated (but classic) barley half-seed experiment that looked at the role of hormones, the embryo, and a bunch of other things involved in seed germination/starch degradation. It was a pain, and I usually got roped into making hundreds of petri plates with different additons to the starch containing media. Last year we did a demo of mashing, this year we had the students do the new experiment.

Basically we have the students do a really mini-mash (1 gm in 10 ml of water), and then use iodine to monitor starch conversion. We had them compare 6-row, 2-row, and Vienna malt. We also had some leftover malts (6 & 2-row) from last year, so I thought, hey, what a great chance to check for crushed malt longevity! The malt from last fall was just crushed and then sealed in a ziploc bag and kept at ~ 70 F for one year. The husks cause some problems so this year I double milled the grains and then removed as much of the husks as possible giving me a malt "flour". I then took this malt and ran it through a coffee grinding to make it really fine. The year old malt (and it's husks) was also ground in a similar manner. Therefore the year-old malt will have less endosperm, gram for gram compared to the fresh stuff.

We've been busy so we hadn't worked all of the bugs out ahead of time so we thought we'd have the students help to figure out the best protocols. That wasn't working so well, so I set up some reactions this morning. For a variety of suspected reasons things weren't working real well (including a faulty incubator) so I set up a number of reactions with the 2-row, and one with the year old 2 row. The students were using RO water for the mash, so I set up a tube with RO water, a tube with RO water plus a pinch of buffer 5.2, a tube with tap water, and since the time zeros were very black I set up one with only 0.5 gms of malt powder in RO water. After incubating for 30 minutes at 150 F I performed the starch assays. We have the students take a 15 min. sample, but I went out for my morning walk around campus so I only did the 30 min.

Results:
All had gone to completion except one, and it was NOT the year old malt. The year old crushed malt (sealed in an airtight ziploc bag) was fully converted within 30 min., actually 35 min. as I took a little extra time for my walk. The one that didn't fully convert was the tap water sample! It was pretty well converted, but not completely. I don't know the campus water profile, but I assume it is high in carbonates like the city water. I suspect the pH was off in this sample. I haven't checked this yet. My wife had to change buildings for her teaching lab while they renovate so things aren't well set up. I didn't have a camera handy, but maybe tonight I'll get some photos of the time zero and 30 min. tubes. Maybe I'll do the whole thing again tonight (all malts) with the 15 min time point too while we do the TA meeting for next week.

I post the results again next year. I'll save some of the finely ground malt powder I just made and check it again next fall. Maybe some 2 year old then too.
 
Back
Top