Correlations between the quality indicators are shown in
Table 2. The difference in 1000 grain weight was not expected since the grains were sieved (ø 2.8 mm and ø 2.4 mm). The expected strong correlation (
Table 2) was confirmed between the total protein share and NIR grain hardness, while the correlation between total pentosans and NIR hardness was somewhat lower. These are not unusual results for hard wheat [
12]. A high correlation (
Table 2) between total pentosans and vitreosity was also determined, but a correlation between soluble pentosans and vitreosity was not found. No significant correlation between the total and soluble pentosans was detected. Water-soluble pentosans of wheat exhibit some unique physical properties; it is also known that soluble pentosan content has an influence on the wort viscosity and membrane filterability (r = 0.98) [
5,
13,
14]. As can be noted from
Table 1, the sums of the total and soluble pentosan values were within the average values for this type of wheat [
15,
16], only sample 6 had a somewhat higher, but acceptable value (0.82% d.wt.). Low to medium negative correlation was determined between the LAT values and all other parameters.
The major indicator of a successful malting process is obtaining wort with a low viscosity and low soluble N share. Considering the values obtained for moisture 48 h after micromalting (
Table 3), certain significant differences between varieties could be observed. This indicator represents the criteria for swelling capacity and reflects all of the biochemical processes during malting. This indicator is significantly bound to the soaking speed and the maximal amount of water a grain can withhold. The ability to quickly absorb water and withhold larger amounts of water indicates a quicker germination (quicker activation of the aleuron layer means subsequently quicker de novo enzyme synthesis and immobilization of the existing enzymes). The ability to absorb larger amounts of water leads to more intense swelling and breakage of starch granules, which enables easier enzyme degradation, thus variety shows higher enzymatic power [
10]. The obtained values were significantly >30%, the minimal value a grain should show after soaking. The third soaking moisture is a valuable information for maltsters, because it represents the maximal water amount a grain (under given process conditions) can soak up. The biggest decrease of viscosity can be obtained during germination of wheat (according to the standard MEBAK procedure with soaking temperature being 14 °C) with a third soaking moisture of 41–45%. It should be clear that the moisture should not fall under 43% for green malt [
17], and this was achieved for all samples (
Table 3). The viscosity of wort is an indirect indicator of cytolysis. Strong cytolysis is often accompanied with increased proteolysis that needs to be contained. The tested varieties had >12.5% of total proteins. Since the process parameters cannot be modified during the micromalting, and in order to obtain the satisfactory values for proteolytic activity (soluble N; Kolbach number 35–38%) [
17,
18], steeping should be conducted with lower moisture content, which ultimately effects the process of citolysis. The obtained results for soluble N were satisfactory (Table 5), so there was no need to lower the moisture content in the grains, thus acting favorably on the citolytic aspect of grain modification.
A 1000 grain weight was a mediocre value for all of the tested varieties and showed no significant correlation with any of the other indicators. This is why it was not considered for further investigation. In comparison to the starting vitreosity of wheat, malt grain, and starting wheat grain, it can be noted that varieties 1, 3, and 7 possessed temporary vitreosity (mealy varieties) while malts obtained from varieties 2, 4, 5, and 6 showed partial permanent vitreosity. Significant correlations were obtained for values of diastatic power, formol N, and Kolbach indexes. The share of fine extract should be as high as it can, certainly >83% (83–85%) [
3]. Varieties 1 and 2 were satisfactory; varieties 3, 4, 6, and 7 showed somewhat lower values and variety 5 resulted in low fine extract values. Considering that the extract difference results showed as being very good, these fine extract values can be attributed to the increased protein share. This is especially pronounced in the comparison between varieties 2 and 5. The F/G difference is an indicator of successful endosperm cell wall degradation. High values of F/G mean that the endosperm is not well degraded and a lower share of fermentable sugars can be expected in such malts. Even though a slight, but clear difference was noted between samples 1, 3, 4, 5 and 2, 6, 7, the obtained values were satisfactory for all varieties. Significant positive correlations were obtained for filtration time and wort pH. Negative correlation was determined between 1000 grain weight. Saccharification time was within the recommended limits of 10–15 min. Wort pH for all samples was somewhat higher than recommended (5.9–6.1), except for samples 4 and 5. The negative correlation was determined between the total proteins, VZ 45 °C, diastatic power, soluble N, FAN, and formol N. This strong negative correlation between proteolytic and cytolytic parameters was expected because the protein degradation results in free amino acids that react with sugars in water solution and produce acidic melanoidins, lowering the pH value of wort. On the other hand, protein degradation is conditioned by a lower pH. The already mentioned positive correlation with the F/G difference was a result of lower endosperm degradation during mashing, and resulted in less accessible substrate for the aforementioned reactions. A strong positive correlation was determined with filtration time, also easily explainable with the lower degradation of endosperm. The color and the color after cooking were within the recommended values for all samples, except for sample 5, while samples 2, 4, and 5 had increased values for this parameter. Proteolytic events and the parameters that measure their successfulness should mostly influence the color, especially FAN [
18,
20]. However, the strong correlation was obtained only with the viscosity of wort and diastatic power. The viscosity of wort gives an insight into the cytolytic degradation of malt. Wort viscosity and its influence on the production process and beer quality has been well investigated [
18,
21]. The general recommendation for wheat malt is to be as low as possible, not over 1.65 mPa×s 8.6%e. All tested samples showed excellent viscosity. It should be emphasized that a strong positive correlation was determined between color of wort, while a correlation with F/G difference, filtration time, and VZ 45 °C (Hartong number) was lacking. All varieties had diastatic power values close to the lower limit recommendation (250–420 °WK). This mostly reflects the activity of egzoenzymes for starch degradation, which increase the content of maltose in wort. The lack of positive correlation with LAT was unexpected. A strong positive correlation was established between wort color and VZ 45 °C, FAN, and formol N. A negative correlation, as expected, was established with pH. VZ 45 °C is an indirect indicator of cytolytic and proteolytic enzyme activity that enable the production of free amino acids and lower peptides, easily assimilable by yeasts. The obtained values were satisfactory for all varieties, except for variety 7, whose values were significantly over the recommendation to not go over the Kolbach index by 2 units. The Kolbach index should be >33 for malts with 12.5% total proteins. However, it should be emphasized that in this case, the worts contained a significantly higher share of proteins (except for samples 2 and 7). The expected strong correlations between diastatic power, FAN, and formol N were obtained. A strong negative correlation with the high molecular N share in the total soluble N was determined. According to Narziss [
3], this relation should not go over 45% while the tested varieties showed a span of 48.3–53.8% (
Table 5), so the obtained correlation is not surprising. This increase of high-molecular N (potentially damaging N for colloidal stability and useless for yeast [
5]) indicates a low proteolysis. Total proteins have a central role in the quality and structure of wheat malt. They influence the reduction of the extract and the increase in soluble N and low-molecular N (formol N and FAN) [
18]. N fractions are mostly non-fermentable, so the increase in total N should lead to reduced LAT. Sacher [
18], however, established that the increase of total proteins acts by decelerating their degradation. This causes an extremely slow increase of soluble N with the increase of total protein content in the grain. The quotient of these two values may also have a downward trend. It has already been mentioned that the tested assortment showed increased values for total proteins. The recommended values (12–13% d.wt.) were only detected in sample 2. Wheat samples mostly differed among each other considering the total protein content (
Table 1) and protein degree of degradation during malting (Δm total proteins in wheat: wheat malt 1 = 0.78%; 2 = 1.2%; 3 = 0.57%; 4 = 1.01%; 5 = 0.45%; 6 = 0.7, and 7 = 1.99%). No significant correlation was established between the content of total proteins, their reduction during malting, and total losses during malting. According to the literature, soluble N values can range from 700–900 mg/100 g d.wt.; [
9], 700–770 mg/100 g d.wt., [
3]; <730 mg/100 g d.wt.; [
18]. All tested samples were below <900 mg/100 g d.wt, and only samples 4 and 5 were above 770 mg/100 g d.wt. Samples 1 and 2 showed excellent values regarding this indicator. It can be stated that the tested assortment showed the effect of proteolysis deceleration and saturation. The expected strong negative correlation was established for fine and coarse extracts. A strong positive correlation was detected for soluble N, but not with other indicators of proteolysis efficiency. Positive correlation was established between soluble N and FAN, and a strong negative correlation with fine and coarse extracts. The expected strong correlation between soluble N and VZ 45 °C was neglected. A negative correlation between high-molecular N and FAN was established. The soluble N/FAN quotient indicates how well the soluble proteins are degraded. In wheat malt, this quotient should be much lower (9–16%) than in barley malt (19–24%). FAN was within the recommended values for all samples. Formol N represents the low-molecular N obtained by the degradation of amino acids and lower peptides and was inside the recommended values for all samples. Its strong positive correlation with FAN, diastatic power, and VZ 45 °C was established. The Kolbach index represents the share of soluble N in total N and is an indicator of successful proteolytic malt degradation. The Kolbach index for wheat malt should be ˃38. All samples showed significantly lower values because of the aforementioned lower soluble N with regard to the starting total proteins. There was a strong positive correlation between Kolbach index, vitreosity, and the malts’ diastatic power.