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Staggered Nutrient Additions


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#1 MtnBrewer

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Posted 11 April 2009 - 08:22 PM

Staggered Nutrient AdditionsAs a mead maker, you have taken up an ancient craft that endeavors to make the proverbial "nectar of the gods". Your success in this endeavor will be equal to the extent to which you have used quality ingredients and the extent to which your yeast have a strong and clean fermentation. Meads have exquisite flavors and aromas that cannot be found in any other type of beverage. However, due to the delicate nature of these flavors, they won't do much to hide any flaws in your technique as a mead maker.The most important thing you can do to help your yeast is to provide them with a continuous supply of nutrients (especially nitrogen and phosphate) and to keep them healthy throughout the fermentation. Such is the purpose of a Staggered Nutrient Addition schedule.Honey is quite lacking in nutrients that yeast require, especially nitrogen. If the yeast are pitched into a must with an inadequate level of nutrients, there are two likely outcomes:
    [*]The yeast will become metabolically stressed and ferment the must slowly while producing undesirable off-flavors. As a result, the mead will require extended aging in order for those flavors to mellow.[*]Having run out of adequate nutrients, the yeast may prematurely become dormant and drop out of suspension, leaving you with a stuck fermentation.[/list]For anyone using dry yeast, the mead making process and the addition of nutrients will start with the re-hydration of your yeast.In an article published in Zymurgy, Ken Schramm writes:
      [*]Rehydration at 104°F with Go-Ferm or other organic rehydration nutrient at a rate of 1.25 grams nutrient per gram of yeast. In all cases, addition of nutrients by weight will be more accurate than by volume...[*]Addition of 3 grams (approximately 0.75 teaspoon) Fermaid K, plus 4 grams (1 teaspoon) DAP per 5 gallons of must with a vigorous aeration at the end of the lag phase (six to 12 hours, at the start of obvious fermentation activity). This equates to 21 ounces Fermaid K plus 28 ounces DAP per 1.000 gallons. For gravities above 1.125, increase these amounts by an additional 25 percent.[*]Addition of 1 gram (0.25 teaspoon) DAP, plus 1 gram (0.25 teaspoon) Fermaid K with a vigorous aeration at 12-hour intervals until 50 percent sugar depletion or five days, whichever occurs first (7 ounces DAP plus 3.5 ounces Fermaid K per 1,000 gallons).[*]Supplementing the potassium levels to a minimum of 300 ppm with a potassium source... For home meadmakers, potassium bitartrate or potassium phosphate are viable options.[/list]As an alternative to Ken Schramm's approach, you could use the technique developed by HighTest, one of the pioneers of using nutrient additions:HighTest's Basic Mead, Cider, & Perry NAS (rev 2) - Sized for a 5 Gal Batch:- At inoculation - 4.5g Superfood [or Fermaid-K] & 4.5g DAP- At active fermentation - 2.8g Superfood [or Fermaid-K] & 2.8g DAP- Just before fermentation mid-point - 1.8g Superfood [or Fermaid-K] & 1.8g DAPNotes:
        [*]Active fermentation is defined when the Brix drops 2-3 degrees [This stage typically occurs within 8-24 hrs][*]The fermentation mid-point can be determined by (OG+TG)/2[/list]Depending upon which nutrient is used, this protocol adds 167 - 176 ppm of timed yeast available nitrogen (YAN) to whatever may be available from the must. YAN is also known as Free Amino Nitrogen (FAN).For those of you who do not have digital scales:- 1 tsp of SuperFood weighs ~ 2.4g- 1 tsp of powdered DAP weighs ~3.9g- 1 tsp of Fermaid-K weighs ~4.0g.The nutrient quanities were changed based on conversation with Dr. Clayton Cone wherein I learned that he recommended the bulk of the nutrients be added before 30% sugar depletion - the yeast are usually well into their stationary phase at 50% sugar depletion and cannot utilize the nutrients as well as they can before 30% depletion. As such, the NAS now adds 85% of the nutrient nitrogen before 30% sugar depletion.Following a Staggered Nutrient Addition schedule as recommended by Ken Schramm and HighTest should greatly shorten the amount of time required for both fermentation and aging of your meads. In addition, by nurturing your yeast throughout the fermentation process, you will dramatically reduce the chances of running into a stuck fermentation.I'd like to give special thanks to Ken, HighTest and Zymurgy for allowing us to reprint their excellent information. Cheers and happy mead making!-Matt the Mead MakerReferences:Schramm, Ken. "Optimizing Honey Fermentation", Zymurgy November/December 2005, page 24HighTest "Staggered Nutrient & DAP Addition", www.BrewBoard.comLallemand Nutrient Addition Guidelines [PDF]Go-Ferm Rehydration Instructions [PDF]


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