Issue link: https://read.dmtmag.com/i/705606
w w w. v w m m e d i a . c o m J u l y - A u g 2 016 | V I N E YA R D & W I N E RY M A N A G E M E N T 5 1 acids should be added at inocula- tion, before ammonium ions. "At this stage, yeast can assimilate amino acids to build 'healthy' cells that are resistant to stress condi- tions and produce aromas." As fermentation progresses, the rising alcohol levels begin to stress the yeast. "At one-third of sugar depletion, yeast start to become stressed and the assimilation of nitrogen is lower," says Santos. "To complete fermentation and increase their alcohol resistance, they need fast and easy nutrients to absorb [ammonium ions] and survival factors [sterols and unsat- urated fatty acids] with oxygen." There's a case for suggesting that oxygen should be regarded as a yeast nutrient, because it helps yeast produce sterols, which build stronger membranes, and help them resist the effects of rising alcohol levels in the must. "In case of strong nitrogen deficiency, must needs to be corrected by an addi- tion of ammonium ions 24 to 48 hours after inoculation [after the addition of amino acids]." Santos emphasizes that addi- tions must be made no later than when half sugar depletion occurs. "Late nutrient additions are less effective for yeast activity and can promote development of spoil- age organisms, appearance of off- mineral salts), Nutriferm Advance (a complex nutrient made from yeast hulls, ammonium phosphates and cellulose, which provides ammo- nium ions, sterols and unsaturated fatty acids) and Nutriferm No Stop (yeast hulls rich in sterols and unsat- urated long-chain fatty acids, which, when used at mid-fermentation, helps maintain yeast membrane integrity). DAP VS. COMPLEX ORGANICS While DAP is the most popular nitrogen addition in winemaking, there's currently some discussion that this might be making the prob- lems it's intended to solve worse. It's been described as "junk food for yeast," altering their metabolic pathways in unfavorable ways. Some work from the Australian Wine Research Institute has shown that DAP may in fact exacerbate some of the reductive issues that it's being used to counter. For this reason, where cost isn't complete- ly limiting, many winemakers are using more complex organic nitro- gen supplements. S a m H a r r o p i s a c o n s u l t i n g winemaker who works widely in Europe and New Zealand. "I tend to supplement anything below 200 YAN," he says, "but I don't use DAP unless it's a commercial prod- flavors and formation of biogenic amines," he says. Enartis makes a range of differ- ent nutrients, including Nutriferm Energy (which provides quickly absorbed amino acids for the first part of fermentation plus vitamins and mineral salts), Nutriferm Arom (rich in amino acids, which are absorbed at the end of the growth phase and are aromatic precursors of fermentation aromas), Nutriferm Arom Plus (contains a high content of more slowly absorbed amino acids selected for their aromatic precursors potential, vitamins and Jose Santos of Enartis USA advises that amino acids be added at inoculation, before ammonium ions. LAFFORT USA - 1460 Cader Lane, Suite C - Petaluma, CA 94954 Phone: (707) 775-4530 - Fax: (707) 775-4537 - laffortusa@laffort.com - www.laffort.com SUPERSTART®Blanc (White and Rosé wines) Optimizes the production and aromatic revelation by yeasts, producing more aromatic wines while also guaranteeing stronger fermentation completion. (Red wines) Improves yeast cell longevity under stressful conditions and increases yeast tolerance to high temperatures and alcohol. BREVET N° F.2.736.651 SUPERSTART® Rouge N at u r a l Y e a s t O p t i m i z at i O N NUTRIMENT / NUTRIENT 1 kg USAGE ŒNOLOGIQUE œnologie ricerca innovación i n n o v a t i o n nature PRÉPARATEUR DE LEVURE POUR VIN ROUGE Brevet n° F 2.736.651 - Amélioration de la longévité des levures dans des conditions de stress SUPERSTART ® Rouge R NATURAL YEAST OPTIMIZATION SUPERSTART