It’s the Fermentation

April 12, 2009 07:00 PM

by Rick Lundquist

I recently had dinner with two oenologists (wine scientists). Being an oenologist is very much like being a dairy nutritionist except: 1) it's more sophisticated, 2) if you get a stain on your clothes at work it doesn't stink, and 3) other people are really interested in what you do. We had a lot of interesting discussions about fermentation; from grapes to silage.

With grapes as with corn, alfalfa, grass or small grains, you are at the mercy of Mother Nature as to how your "vintage” matures in the field. But what you do with the crop after its harvested has a huge impact on the final product. Once the grapes are harvested, wine makers may actually add air during fermentation. We always want to exclude air when making silage. Winemakers may add various yeast strains to make a good wine. Yeast is generally a bad thing for silage, a result of poor fermentation and causing poor stability.

Winemakers may also ferment at different temperatures. But excessive heating during ensiling destroys nutrients. Oenologists often use adjectives like fruity, yeasty and buttery to describe a good wine. These smells describe lousy silage that typically has higher yeast populations, high pH, poor nutrient retention, heating, poor bunk stability and palatability problems. These silages may also have higher mold counts and mycotoxin issues. Well fermented silage has a vinegary or acetic smell. So what makes good silage generally makes crummy wine. But one thing they do have in common is once the wine bottle or the silage pit is opened, its starts to go bad if not properly handled.

Key factors for making good silage:

  1. Harvesting at the proper maturity and moisture.
  2. Chopping at the optimum length for good rumination and effective packing.
  3. Filling quickly and packing effectively to get the air out.
  4. Using an inoculant targeted for the crop.
  5. Covering and sealing to keep air out.  
  6. Managing the feedout.

 I learned at lot by comparing notes with the wine scientists. Although I'm not sure they were as intrigued with making silage as I was with making wine.

--Rick Lundquist is an independent nutrition and management consultant based in Duluth, Minn. You can contact him at

This column is part of the Dairy Today e-Update newsletter, which is delivered to subscribers biweekly and includes dairy industry analysis, dairy nutrition information as well as the latest dairy headline news. Click here to subscribe.



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