Showing papers in "American Journal of Enology and Viticulture in 1966"

The Total Phenolic Content of Grape Berries during the Maturation of Several Varieties

Abstract: A study was made during two seasons of the total extractable phenolic substances assayed by the Folin-Denis colorimetric procedure from representative entire berries of a total of 12 varieties of grapes (7 without anthocyanins, 5 with: 2 Vitis labrusca , 10 Vitis vinifera ) from mid-July until they were commercially ripe. A general trend downward in total phenols per unit weight of berry was found. However, the total phenol content per berry actually increased rather rapidly over a considerable portion of the development and ripening period. A considerably greater biochemical activity of the total phenolic substances carrying over into later periods of ripening than expected was observed not only as indicated by this net synthesis or accumulation in the berry, but also by shorter-term increases and decreases of considerable magnitude. Additional criteria of practical use for harvesting grapes for improved quality, particularly regarding wine-tannin relationships as well as new understanding of the grape9s physiology and biochemistry, are anticipated from further extension of these studies. Great differences were found among the varieties tested in total extractable phenols per single berry or per unit weight of berry and in browning tendency of the juice. There appeared to be generally greater browning in the riper harvests for white grapes and during onset of anthocyanin synthesis in red grapes.

Contributions of Grape Phenols to Oxygen Absorption and Browning of Wines

Abstract: The reaction of oxygen with wine in its normal acidic condition was in proportion to the total phenol content if the wine samples differed considerably in phenol content, but the reaction was fairly slow and did not reach an end-point in a convenient length of time even at an elevated temperature. Maximum oxygen consumption by wines made very alkaline was rapid, and reproducible values were obtained with a Warburg technique. These values were of the order of 200-600 cc O2/l for red table wines and 50-100 cc O2/l for white table wines. The oxygen consumption per unit phenol of wines or different purified phenol fractions under alkaline conditions was not constant, indicating differences related to the relative content of specific phenolic substances. All phenolic fractions tested did, however, absorb considerable oxygen, and white wines took up relatively more oxygen per unit phenol than did red wine. Studies of both enzymatic and non-enzymatic browning indicated that the catechin fraction was most important in browning. The catechin fraction's oxidation products appear to be capable of accounting for the color of most white wines, whether very light or a dark amber. An analytical technique using the vanillin versus Folin-Ciocalteu assays has also been proposed as a criterion of a wine's tendency to brown.

Flavor Effects and Adsorptive Properties of Purified Fractions of Grape-Seed Phenols

Abstract: Grape seed phenolics were extracted and separated into three distinct groups of compounds. The separated fractions were evaluated in turn for their sensory effects in water and in wine with respect to their thresholds for astringency, bitterness, and effect on taste interaction with acidity. If was found that the three fractions have considerably different flavor effects, both qualitatively and quantitatively. The catechin fraction was bitter but not astringent at levels likely to occur in wine. The leucoanthocyanin fraction and the condensed tannin fraction were both bitter and astringent. All three affected the judges9 reaction to acidity by moderating the apparent sour taste when added at levels near threshold. All three fractions appear capable of important effects on these quality factors at levels which may occur in white wines and certainly do occur in rose and red wines. The condensed tannin fraction contributed the most intense flavor effects on a weight basis, and the evident flavor effects of the phenolic substances in wine were found to be 10 to 100 times as intense as previously noted. The levels present in a red wine are about 10 to 100 times the level barely detectable in a white wine. A comparison was made of the adsorptive properties of casein, gelatin, isinglass, nylon, and insoluble polyvinylpyrrolidone with respect to these phenolic fractions. Large differences were found in relative affinity for the different phenolic fractions. The PVP had a greater capacity in phenol per unit weight than did nylon, and the proteins were greater yet. The synthetic resins had a greater affinity for the smaller molecules than for the condensed tannins, and the proteins were the reverse, under the conditions tested. The resins had considerable affinity for all the fractions in column tests, but, as fining agents the proteins showed no affinity for the catechin fraction under our conditions.

The Relation of Anthocyanin Composition to Color Stability of New York State Wines

Abstract: The qualitative diversity of anthocyanin pigments in the grapes of New York is reported. Differences in hue and resistance to decolorization and browning were observed. Diglucosides proved to be more stable to decolorization than the corresponding monoglucosides, but the latter were less prone to browning. Malvidin and peonidin were most stable, and delphinidin least stable, of the ten pigments studied. Peonidin and cyanidin gave wine a more fiery-red hue than did malvidin, petunidin, and delphinidin, which tended toward a bluish red. These observations will be of assistance in breeding and selecting grapes for red wines. The fallacy of using optical density indices for comparison of monoand diglucoside wines is emphasized.

Density Separations of Wine Grape Berries and Ripeness Distribution

Abstract: It was shown that juice Brix is the primary factor determining grape berry density and that the whole berry9s density is about 98% of the density of its juice This was true for several density classes of two seeded varieties harvested on several dates in two different locations Preliminary tests indicate similar relationships with other varieties Juice Brix from segregated berries Based on these tests is expected to be near or slightly above the Brix of the most dense sucrose solution in which they will sink, if they float in a solution one Brix unit more dense The data presented show the validity and value of the relatively easy technique of density segregation in characterizing a grape berry population Varietal wine prepared from two musts at essentially the same average Brix is often quite different Part of this difference may lie in the ripeness distribution making up the average Brix, and density segregation can elucidate this point Application of the methods outlined to the detection, study, and use in variety selection of a characteristic physiological limit to sugar accumulation warrants further study The technique is capable of selecting fruit from a single harvest so that ripeness differences relatively free of weather differences can be studied Berries of relatively rare composition can be selected from a large population Further study may even disclose commercial utility in making quality separations among whole clusters or, eventually, mechanicaly harvested berries

Fermentation Rates of Grape Juice. II Effect of Initial °Brix, pH, and Fermentation Temperature

Abstract: Yeast cell growth rate and grape juice fermentation rate were shown to be dependent on initial Brix and pH as well as on fermentation temperature. Variation between pH 3.5 and 4.0 caused small but significant fermentation rate changes. Changes are large at pH 3.0 compared with the other two pHs. Optimum fermentation rates for grape juice occur between 15 and 20° initial Brix, and so does optimum yeast growth rate with these media. Temperature interactions with pH were demonstrated on rate of fermentation and yeast growth rates. The lower the pH with increasing temperature the greater the effects found on rate of fermentation and rate of yeast growth.

Changes in Concentration of Organic Acids, Sugars, and Amino Acids in Grape Leaves

Abstract: Glucose, fructose, sucrose, malate, tartrate, and 22 free amino acids ware determined in `Thompson Seedless9 grape leaves during the first 36 days of growth and throughout the growing season. The glucose and fructose content of leaves increased 3-to-5-fold between the second and third weeks after budburst and remained high until senescent. Sucrose of immature leaves was generally less than glucose and fructose. During the latter part of the growing season, sucrose was the main sugar in all leaves. The tartrate content increased very rapidly during leaf elongation to a maximum concentration 4 weeks after budburst. Malate continued to increase until late in the season. The amount of both acids decreased rapidly after senescence. Twelve to 27% of the total acidity was accounted for by acids other than tartaric and malic. Twenty-two free amino acids were identified and measured quantitatively. Proline and threonine predominated during the first week of growth. Free amino nitrogen decreased more than 50% between the 4th and 36th days of leaf growth. Most of the loss was due to decreases in proline, threonine, asparagine, glutamine, β-alanine, valine, serine, pipecolic acid, and tryptophan. In mature leaves the principal amino acids were α-alanine, glutamic acid, aspartic acid, γ-aminobutyric acid, and proline.

Fermentation Rates of Grape Juice. III. Effects of Initial Ethyl Alcohol, pH, and Fermentation Temperature

Abstract: The effects of initial alcohol on grape juice fermentation have been studied by observing interactions with temperature and pH. Initial alcohol delayed and limited fermentation. At pH 3.0 the effects on the lower initial alcohols were inhibiting, but, as the initial alcohols increased above 4% by volume, adjustments to this pH responded similarly to those at pH 3.5 and 4.0. Fermentation rates were diminished rapidly at 91°F at over 4% initial alcohol. At 70°F, rate response to initial alcohol changes was nearly linear. At 50°F, fermentation rates are affected less drastically by initial alcohol concentrations above 4%. Viable cell count data indicate that the above responses are due mainly to growth-limiting or killing effects on the yeast.

Paper Chromatography of Phenolic Compounds from Grapes, Particularly Seeds, and Some Variety-Ripeness Relationships

Abstract: A simple standardized technique for two-dimensional paper chromatographic "mapping" and estimation of the relative amounts of the phenolic substances in grape extracts was presented. This technique was applied to the study of weekly harvests of 12 grape varieties. The berry pulp tended to reflect the juice and seeds in phenolic composition. The juice phenolics, as a rule, were predominantly blue-fluorescing substances resembling chlorogenic acid and its analogs. Calzin and one of its parents, Refosco, were unique among 34 varieties tested in having a considerable content of astringent tannin in the juice. Skin extracts were quite variable in qualitative phenolic composition by variety, especially considering, but in addition to, the presence or absence of anthocyanins. The phenolic composition of the seeds, however, followed a similar pattern in red or white grapes and in varieties with parentage from two species of Vitis . Among a total of about 25 differentiated substances readily oxidized by FeCl 3 -K 3 Fe-(CN) 6 and considered as phenols, the majority were present in the seeds of all varieties at similar stages, and usually in roughly similar proportions. Varietal differences did occur with respect to the presence or absence of a few of the substances and the relative amounts of those present per unit of total phenol. The nature of several of the substances was outlined, and, in particular, evidence was presented that one was catechin, one was epicatechin, and a third was epicatechin gallate. Although these flavanols have been reported in grapes (4, 6) previously, epicatechin gallate has not always been found in seeds (6). A considerable metabolism of phenolic substances in seeds during ripening was found even up to the last stages, as shown by the appearance or increase of some and the decrease of others in relation to a unit of total phenol.

The effect of some Cultural Practices on Nitrogen and Fruitfulness in the Sultana Vine

Abstract: In a small field trial over two seasons, sowing a cereal crop between the rows of Sultana vines at the beginning of September, and turning it in in late November a few days after full flowering for the vines, led to reduced leaf nitrogen in the vines over the period of differentiation of inflorescence primordia. In the second season there was a 27% increase in bunches per vine on such vines, compared with vines treated according to good district practice and already yielding more than district average. Since there was no sign of moisture stress due to the cereal, and no reduction in berry set, which is known to be affected by moisture stress, the increase in bunch number is associated with reduced nitrogen, but the treatment caused weakening of some of the vines and reduced yield in the following year and was discontinued. Further attempts to lower soil nitrogen enough to increase number without seriously affecting vine vigor have not succeeded.

The Technology of Passion Fruit and Mango Wines

Abstract: The two fruits studied (passion fruit, "Maracuya" variety, and mango, "Hilacha" variety) can be recommended as raw materials for the production of good-quality fruit wines; passion fruit for dessert wine, and mango for white semisweet table wine. Technological schemes for the production of these wines are presented. Tables describing the taste and chemical composition of these wines are given which show necessary specifications for production.

Thinning Effects of Bloomtime Gibberellin Sprays on Thompson Seedless Table Grapes

Abstract: Gibberellin sprays applied during the bloom period to Thompson Seedless vines used for table grapes resulted in a decrease in berry set, an increase in berry size, and higher soluble solids. The berries were also elongated by the gibberellin treatments. Gibberellin concentrations of 10 and 20 ppm produced loose, attractive clusters. Concentrations of 25, 50, and 100 ppm induced the development of undesirable shot berries. There were no significant differences in berry set between the 10- and 20-ppm treatments or between spraying at 10 and 70% bloom. The berry thinning effect from the gibberellin was relatively uniform throughout the cluster. This is important in market acceptance of table grapes.

Gas Chromatographic Comparison of Volatile Aroma Materials Extracted from Eight Different Muscat-Flavored Varieties Of Vitis Vinifera

Abstract: Eight muscat flavored grape varieties— Aleatico, Early Muscat, Malvasia bianca, Muscat of Alexandria, Muscat Hamburg, Orange Muscat, and two new varieties of intense flavor, P 20-59 and Q 26-39—were studied from the point of view of their volatile constituents. Samples of the order of 100 lb were reduced to puree in the Langsenkamp pulper after washing and hand-destemming. The volatiles were stripped from the puree at reduced pressure in a Precision laboratory evaporator, and the distillate from the evaporator was extracted with the pentane-ether azeotrope to isolate the desired volatile components. The volatile aroma concentrates obtained on distilling away the extracting solvent through a Vigreaux column were analyzed gas chromatographically on a 10 ft x ⅛ in FFAP column in an Aerograph 660 instrument. Low-boiling volatile constituents were separated using a programmed temperature regime, whereas the higher-boiling constituents were analyzed isothermally in the gas chromatgraph. Infrared spectra were determined on a number of the isolated and repurified volatile components. Significant variations in relative concentrations of a number of the components of high intrinsic odor were found. Orange Muscat and P 20-59 contained the highest concentrations of linalool. Early Muscat and Q 26-39 were intermediate in concentration of this substance, while the rest of the varieties contained only small amounts. Hexanal and trans-hex-2-enal were present in Early Muscat, Malvasia bianca, and Muscat of Alexandria at relatively high concentrations, while the other varieties contained lesser amounts. The corresponding alcohols, hexanol and trans-hex-2-en-l-ol, were present in relatively large concentrations in all varieties except P 20-59, and there seemed to be no inverse relationship between the aldehyde and alcohol concentrations.

Some lactobacilli associated with decomposition of tartaric acid in wine

Abstract: One hundred and eighty-four pure cultures of lactobacilli were isolated from environments where these microorganisms are commonly found. Induction of tartrate fermentation was successful with 64 of these isolates. Twenty-four of these isolates were heterofermentative, and 40 were homofermentative. Successful isolation of tartrate-fermenting lactobacilli required a tartrate broth containing yeast autolysate, adjusted to pH 3.8-4.0, and exclusion of oxygen. If the latter two conditions are not met, other microorganisms quickly become established which are capable of more rapid tartrate degradation. The ability of certain lactobacilli to dissimilate tartrate in full-strength table wine was demonstrated. It was observed, however, that yeast autolysate must be added to the wine. Succinic acid, acetic acid, and carbon dioxide are formed by the dissimilation of tartrate by both homo and heterofermenmentative species of Lactobacillus . Propionic acid, which had been reported to be among the end products of tartrate fermentation by organisms thought to be lactobacilli, was not found.

Pichia Membranaefaciens, A Yeast Causing Film Formation and Off-Flavor in Table Wine

Abstract: A film-forming yeast causing off-aroma and flavor in table wine has been isolated and identified as Pichia membranaefaciens Hansen. It can grow in wine containing up to 11% by volume of ethanol but cannot tolerate any free sulfur dioxide. Its optimum growth temperature is 20°C, and no growth is observed at 30°C. During growth on wine the yeast produces acetaldehyde, ethyl acetate, iso-amyl acetate, and an unidentified compound, the last being quantitatively the most important. The role of the yeast in wine spoilage is discussed and control procedures are given.

Fermentation Rates of Grape Juice. IV. Compositional Changes Affecting Prediction Equations

Abstract: The ammonia and total nitrogen composition of a number of grape juices were determined and, with the degree Brix and pH, related to fermentation rates. Varied growing conditions, varieties, and grape maturities were investigated. Nitrogen balances on the juice were determined to a limited extent. Prediction equations for fermentation rate estimation were derived for three fermentation temperatures based on °Brix, pH, and total Kjeldahl nitrogen analysis of the juice.

Volatile Components of Sherry Wine. II. Isolation and Identification of N-(2-Phenethyl) Acetamide and N-Isoamylacetamide

Abstract: N-(2-phenethyl)acetamide and N-isoamyl-acetamide were identified as components of a submerged-culture sherry. The infrared spectra of the N-isoamyl and N-(2-phenethyl)amides of acetoacetic and acetic acids are presented. It seems unlikely that the secondary amides found in the wine result from herbicides used in the vineyard or that they result from fungi or rot present on the grapes at harvest time or from the special conditions of the submergedculture fermentation process. Rather, it seems likely that the secondary amides are by-products of the normal alcoholic fermentation processes in converting grapes to wine. The role played by secondary amides in the aroma and taste of wines remains undetermined.

Identification of Some Acetals in an Extract of Submerged-Culture Flor Sherry

Abstract: The essence extracted from ten gallons of submerged-culture flor sherry by means of methylene chloride was found to contain the following acetaldehyde acetals: ethylact.-amyl, ethylisoamyl, diact.-amyl, act.-amylisoamyl, diisoamyl, ethylphenethyl, act.-amylphenethyl, and isoamylphenethyl. Infrared spectra for these eight acetals are presented. The aromas of these acetals are intense and characteristic, suggesting that (if they be present in the wine) the simple acetal-to-aldehyde ratio as a criterion of sherry quality may need modification to reflect variations in acetal and carbonyl species as well as concentrations.

L (+) Lactic Acid and D (-) Lactic Acid in Wines

Abstract: The two stereoisomeric forms of lactic acid have been detected in wines and measured quantitatively by the enzymatic determination of L(+) lactic acid. A chemical determination of the total amount of lactic acid permits the measurement of the D(—) lactic acid by differences. Alcoholic fermentation forms small quantities of D(-) lactic acid while malo-lactic fermentation produces large quantities of the L(+) lactic acid isomer.

Two-Stage Generation of Sulfur Dioxide within closed Containers to Control Decay of Table Grapes

Abstract: A two-stage system for controlled generation of sulfur dioxide to retard spread of decay from Botrytis cinerea Pers. in packed table grapes was developed for closed containers holding 27 pounds of fruit, either: 1) unvented telescope paraffin-plastic-coated corrugated paper; or 2) wooden lugs with completely closed polyethylene-coated chip-board liners. For the first-stage system, tissue-paper packets containing sodium bisulfite were distributed evenly in excelsior cushion pads above and below the fruit. Dose per container was 1.8-5.4 grams, divided among 12 packets. For the second-stage, sodium bisulfite was sealed in paraffin-coated tubes of 2 x 150 mm evenly spaced in the pads. Dose per container was 4.8-10.8 grams, distributed in 6 tubes. Packed containers were closed, precooled, and stored at 31 °F. Within 2 hours of closure, first-stage sulfur dioxide was detected, in some experiments reaching maximum concentration (12-40 ppm, depending on dose) by the second day. The second-stage system started generating sulfur dioxide after 5 days reaching maximum concentration (2-40 ppm) by the 12th day. Containers with high second-stage doses still contained 2-4 ppm of sulfur dioxide in the air at 53 days. Low-dose treatments were exhausted in about 40 days. For periods up to 30 days, high-dose first and second stages gave decay control equal to or better than that in the control—vented containers fumigated initially with sulfur dioxide and weekly thereafter. However, this dose caused appreciable bleaching. The low-dose first and second stages produced less or no more bleaching than that in the controls. Berries and stems in closed containers were conspicuously more turgid and fresh than those in the controls, because of considerably less water loss. Storage temperatures to 39°F had no effect on exposure to sulfur dioxide but did increase spread of decay. A simulated export shipment test demonstrated that the two-stage system without sawdust protected grapes from decay as well as the NaHSO3-sawdust method now used.

Review of Applications of Enzymatic Methods to the Determination of some Organic Acids in Wines

Abstract: The essential characteristics of photometric enzymatic analyses are discussed along with application of these techniques to the determination of pyruvic acid, 2-ketoglutaric acid, malic acid, and L(+) lactic acid in wines. These determinations have shown for the first time the presence in wines of keto acids at levels of some tens (and even in some cases hundreds) of milligrams per liter. These simple specific and rapid enzymatic techniques permit the study of numerous intermediate metabolites which exist in small quantities in a natural material, the precise determination of which is very difficult in complex media such as wines Thus, a new path is opened in the progress of analytical enology and understanding of fermentation.

A General Survey of the Free Amino Acids in the Genus Vitis

Abstract: Leaves from 23 species and berries from 20 species of Vitis were examined by twodimensional paper chromatography for free amino acids and other ninhydrin-reacting compounds at three stages of development. Thirty-two amino acids were identified in the various species. In addition, eight unidentified amino compounds were detected. Large amounts of free hydroxyproline and an unidentified amino acid were present in immature fruit and leaves (sampled in June and July) of five species: V. aestivalis, V. berlandieri, V. cinerea, V. rufotomentosa , and V. simpsoni 9pixiala9 . These two amino compounds were either absent or present in only trace amounts in the other Vitis species examined. Quantitatively, there were large differences between the Vitis species in the concentration of the various amino acids, especially with respect to arginine, proline, and asparagine. Pipecolic acid and homoserine varied both qualitatively and quantitatively among species.

Chemical and Sensory Effects of Microorganisms on Grape Musts And Wine

Abstract: Techniques were developed for the infection and decay of grapes by monofungus cultures. Blends of up to 40% juice from decayed Thompson Seedless grapes and the balance from uninfected fruit were fermented by standard enological procedures. Botrytis cinerea, Rhizopus arrhizus, Aspergillus niger and A. flavus had little or no effect on the volatile acidity of either the musts or wines. However, volatile acidity of musts and wines was raised when grapes were decayed by combinations of Acetobacter roseus and Saccharomyces cereviseae with A. niger, R. arrhizus or B. cinerea ; but very little by combinations which included A. flavus . The fixed total acid of the musts and wines was raised only by A. niger , which also lowered the pH of the wines. Wines which did not ferment to dryness were those with appreciable volatile acidity. There were no marked differences in the amount of residual reducing sugar. There was an inverse relation between alcohol and the volatile acid content of the wines. As determined by the Folin-Denis method, wines from grapes decayed by A. flavus were much higher in tannin-like materials than wines from unaffected grapes or from grapes decayed by the other three fungi. These wines had an unusual yellow-pink color.

A New Indicator for Total Acid Determination in Wines

Abstract: The true endpoint of the total acid titration curve in wine seems to be quite close to pH 7.7. Utilization of this pH permits accurate determination of the endpoint electrometrically since the curve is steepest in this region and a small amount of titrant will shift the pH radically. In cases where a pH meter is unavailable, an excellent indicator, Cresol Red, which has a very distinctive color change at this pH, is available. Superior standard deviation figures are found for this analysis when Cresol Red is substituted for phenolphthalein. The answers obtained by titrating to pH 7.7 or the Cresol Red endpoint may be converted to those found with phenolphthalein or pH 8.4 by multiplying by a factor of 1.05.

Gas-Liquid Chromatographic Analysis of Blackberry Wine Extracts Fermented by Different Yeast Strains

Abstract: Four strains of yeast with different fermentation properties were used in the study to ferment blackberries. The wine that resulted was extracted with ethyl chloride, concentrated by distillation and analyzed by gas chromatography. Gas chromatography was found to be an effective method for detecting the fermentation products of yeasts and consequently for differentiating between yeast strains. However, greater instrument sensitivity or a larger amount of the wine would be desirable to detect the compounds present in trace quantities. A tentative identification, using the enrichment technique, was made of several peaks. These, in order, were believed to be: 2, ethyl acetate; 3, ethanol; 4, propanol; 5, isobutanol; 6, butanol; 7, isoamyl alcohol and act-amyl alcohol; 9, methyl octanoate; 10, 2,3-butylene glycol or ethyl octanoate; 13, linalool; and 14, ethyl decanoate. At their high concentrations, the compounds tentatively identified (peaks number 2, 4, 5 and 7) may be expected to contribute to the flavor and aroma of blackberry wine. Certainly, other minor constituents contribute too, and it is possible that certain of these minor constituents, besides being responsible for the organoleptic differences in wines fermented by different yeast strains, are clues to the enzymatic behavior of yeasts.

The Mold Complex of Napa Valley Grapes

Abstract: Over a five-year period, nearly 10% of all Napa Valley grapes were inspected. The tonnage of all mold-infected grapes represented less than 2% of the total crush. Over 98% of the fruit was clean and free of defects. Of the 2% that was infected, over 90% was infected with Botrytis cinerea Pers., approximately 8% with mildew ( Uncinula necator ), and about 2% with other molds identified as Aspergillus sp., Cladosporium sp., and Penicillius sp. There was no significant relationship between the total mold of grapes and the climatic region of the valley where the grapes were grown. Nor did the grape grade, based on sugar-acid ratio, show any relationship to the total mold content. Although possibily influenced by grape variety and time of harvest, the more mature grapes did show lower levels of mold. A considerable increase in mold during the last week of harvest was noted in all years that had over one inch of rain during the harvest season. Seasons with little or no rain maintained a fairly uniform level of mold growth throughout the vintage. The amount of mold varied considerably with the grape variety. Mildew was a factor in only one year, 1963, and its effect upon the total mold complex was appreciable.

A Rapid Flame Photometric Procedure for Determining Calcium in Wine

Abstract: The separation of calcium from wine as oxalate prior to determination by flame photometer, is described. The depressive effect of oxalate on the emission intensity at 622 mµ has been eliminated at the temperature of the air-coal gas flame by dissolving the calcium oxalate in perchloric acid. The method is rapid. Several samples can be processed in an hour, and the results are in good agreement with those obtained from the established ashing-EDTA titration method.