Teach you how to choose malt for craft beer?

As craft beer becomes more and more popular in China, customers have more and more choices of raw materials, and the requirements are getting higher and higher, so how do we brew craft beer to choose an Australian malt suitable for our own brewing beer?

Most of the customers I have contacted over the years when purchasing malt, often neglect to require suppliers to provide malt factory physical and chemical index testing sheet, do not ignore this small test list, this list records Chinese beer malt indicators, statutory 10 project standards, at the same time the enterprise itself to test 10-15 kinds of physical and chemical indicators, these physical and chemical indicators enterprises are to record, if there is a single detection of beer brewing problems, you can also according to malt, hops, The actual use of yeast is used to find answers to questions one by one, so as not to be sick and indiscriminately sought into the doctor. In addition, the production time of each batch of malt is recorded in detail on the test sheet, so that some malt that is faster than the expiration date will not be used. In addition, when purchasing malt, pay attention to the consistency of samples and large goods. Let's talk about the Australian malt standards required for craft beer from the aspects of the national legal indicators of Australian malt and the indicators tested by the company itself.

1. Appearance:

The quality of the appearance directly affects the color, clarity and transparency of the beer, and even affects the taste of the beer. Its production is mainly due to the harvesting, storage, coarse selection and maceration of the barley itself. For example, barley that has been rained during harvesting is itself dirty, and the malt produced is also dirty. Some barley is affected by variety, origin, soil, climate, etc., and itself is white and blue. If the malt looks white and blue-brown from the appearance of the product, you should be cautious and try to do physical and chemical index testing first. In addition, good malt can also be seen from the appearance, for example, some malt, grab a handful to see that the particles are uneven, different sizes, many impurities, gray or blue-brown; Bite a few powdery grains less, glass plasmid more, then this kind of malt is generally mixed with domestic malt or feed barley, so that malt in the physical and chemical indicators can not reach the excellent malt standard.

2. Scent:

It is obvious that the malt aroma of beer is derived from malt, so the aroma of malt determines the aroma of beer, and there are also some non-malt factors. The aroma of malt mainly comes from the drying stage in the germination process. When choosing malt, try to grab a handful and smell it, take a few grains and chew them to see the aroma and texture. If it smells damp, or the aroma is insufficient, then it is not a newly prepared malt, which may have been stored for a long time. It is especially important for beers that want to highlight the wheat flavor.

3. Moisture:

The commercial moisture of malt is determined by the process in the drying stage, and for now, for breweries crushed by mashed wet processing, the level of moisture does not pose a threat to beer quality, mainly affecting the efficiency of the brewery. However, some of them increase moisture in the malt storage process and exceed the standard, which requires the beer manufacturer to weigh the weight while testing the moisture, and should not consider the problem of moisture affecting the quality under the premise that the excess weight is enough to exceed the moisture standard. The general national standard requires moisture to be less than or equal to 5.5%. For brewing craft beer, it is generally dry crushing and has no effect, of course, the premise is that the moisture content of malt in the drying stage must pass, too dry is not enough.

4. Inclusions:

The inclusions come from barley and are divided into two types, one is a grain that can be saccharified and fermented, but it can bring bad taste to beer; One is a non-fermented substance, such as stones, iron filings, dust, etc., on the one hand, it brings its own unpleasant taste to beer; On the other hand, it accelerates the damage of mechanical equipment. The general national standard requires inclusions to be less than or equal to 1.0%. When choosing malt, when you find that there are a lot of dust, stones, and other debris in the malt, then the malt will have a great impact on the beer you brew, of course, some malt due to some wheat husks falling off or some malt roots in the storage, transportation process is a normal phenomenon.

5. 1,000 grain weight:

This is related to the 1,000-grain weight of barley, generally speaking, the 1,000-grain weight of two-sided barley is between 36-45g, and the 1,000-grain weight of hexagonal barley is between 30-40g. After germination, the weight loss is within 20%, fundamentally speaking, the heavier the thousand grains, the better, and the leaching rate of the thousand grains is high, which is beneficial to the benefits of the brewery.

6. Leaching rate:

The amount of malt leaching rate depends on the original barley variety, related to the year and location of its planting, and also has a certain relationship with protein content, and the leaching rate of high-quality malt is usually specified at 79.5-81%. The leaching rate is very important, it is a decisive factor in determining the quantity and cost of beer. Technically, low leaching rates are often due to insufficient protein dissolution. The protein solubility is higher, the leaching rate is also higher, and the improvement of the leaching rate does not mean that the carbohydrate (starch) is dissolved well, but the result of the coordinated action of various enzymes with proteins and carbohydrates. We can't visually identify this indicator, we can only detect it at the time of winemaking.

7. Coarse and fine powder difference:

The difference in coarse and fine powder indicates the degree of solubility of the barley cell wall. The small difference of coarse and fine powder indicates that the cell wall dissolves well, which is conducive to the filtration and improvement of saccharified wort, and the difference of coarse and fine powder affects the utilization rate of raw materials and the filtration speed of wort and beer, and also affects the composition of wort. The coarse and fine powder difference of high-quality malt is less than 2.0%, and the use of malt with low coarse and fine powder difference can increase the yield of beer.

8. Saccharification time:

Although saccharification is the result of the combined action of a, β amylase, the saccharification time can indirectly indicate the amount of a-amylase present in malt. If the saccharification time of light malt exceeds 10-15min, saccharification will be difficult. Malt that does not dissolve well will prolong the mashing time. Appropriately increasing the degree of immersion, implementing low temperature and long-term germination, and increasing the concentration of carbon dioxide in the wheat layer in the later stage of germination are conducive to the generation and accumulation of enzymes, and improving the activity of enzymes can shorten the saccharification time.

9. Chromaticity:

As a brewing index, light malt requires 2.5-5.7EBC, but with the popularity of light beer, breweries' attention to malt chromaticity seems to have become the primary factor of various indicators, some manufacturers require malt chromaticity as low as possible, which is objectively contrary to the base color of barley and roasting coloring, and some manufacturers think that the appearance of malt is bright white, malt chromaticity is light, so someone collected such a sample and analyzed it, some malt appearance although bright white, However, the measured malt boiling color is as high as 9.5EBC, and some malting plants require the darker the color, the better, because people in this area like to drink low-concentration beer, and the low-concentration beer made by the factory is too light in color. For chromaticity, domestic laboratory testing facilities are different, there is EBC colorimetry, the same malt sample, in different laboratories may be as follows: 3.0, 3.1, 3.25, 3.3, 3.5EBC, of which 3.0EBC and 3.5EBC may be caused by visual errors, 3.1, 3.25, 3.3EBC is the estimated reading caused by errors. In addition, there is also iodine solution colorimetry, the operation error is large, should be eliminated, so the EBC colorimeter should be uniformly used. The color palette should be corrected regularly, and it is recommended to gradually adopt the EBC digital display meter. For craft beer, the chromaticity is recommended to be between 3.5-4.5, of course, there are also some special requirements for brewing some special beers.

10. Boil chromaticity:

Boiling chromaticity industry standard requires glycerol temperature 108±2 °C, and according to the test is difficult to ensure such accuracy, glycerol temperature once rising, and then down takes a long time, in addition, glycerol upper middle and lower temperature difference is large, some laboratories use saturated salt water as a constant temperature water bath, boiling state temperature up to 108±1 °C, and the temperature of each point is consistent, the effect is OK, but need to unify the starting temperature. The correlation between boiling color and finished beer color is very good, so that the soluble nitrogen value can be reverse-checked, usually stipulating that the maximum boiling color of light malt is about 8.5EBC, and the measurement value of different laboratories often varies greatly, indicating that this determination should be very careful to do a good job. As a general principle, the malt boiling chromaticity of different batches cannot change too much, otherwise it will bring too much difference in the chromaticity of beer.

11. Filtration speed:

The filtration speed is directly related to the viscosity, and the high viscosity is the slower filtration speed, which of course affects the quality of the mashed batch and wort. The filtration speed also indicates the degree of malt dissolution, which is related to the barley variety, growing conditions, germination method, drying temperature, and malt storage time. The general requirement is less than or equal to 65 minutes.

12. Total nitrogen:

In order to determine the Courbach index, it is necessary to know the protein content of malt, the effect of protein content on beer yield is well known, the higher the protein content, the lower the beer output, but the impact of protein content on beer quality is much lower than people think, looking at the protein content alone, in fact, the range is quite large (9.5%-12%) has no effect, it is important to evaluate together with soluble protein. For craft beer, the protein content should be moderate, not the higher the better.

13. Soluble nitrogen:

可溶性氮是衡量蛋白质溶解程度的重要指标，对麦汁品质有较大影响，一般以库尔巴哈指数表示，在一定程度上也反映了麦芽细胞溶解程度。麦芽的可溶性氮既不能太高也不能太低，以650-750mg/l为宜。如果数值低于这个范围，麦芽的蛋白质溶解度就太低了，虽然这对发酵和酵母繁殖没有大的影响，但会反映啤酒的香气类型，如会使乙醇含量升高，但如果可溶性氮的含量太高，其香气类型不会有什么变化，却对啤酒味道有影响，尤其是酒体会醇厚。使用未发芽谷物，降低溶解蛋白含量，会使啤酒具有“干”的味道。使用蛋白质溶解度低的麦芽也可以达到这种效果，也会使啤酒的酒体变淡薄。糖化对蛋白质溶解仅有一定的影响，因此麦芽的蛋白质显得特别重要。精酿啤酒的溶解度要适中，不能过高或过低。

14.库尔巴哈值(指数)：

库尔巴哈指数是指可溶氮与总氮的比值，用百分比表示，这个指数用于测定蛋白质降解，在考虑到总蛋白含量的同时，能很好地评价蛋白质的各种关系。该指数通常规定为38%-46%，如果总蛋白偏离通常的10%-11%的含量范围，应更多注意的是可溶性氮而不是库尔巴哈值。

15.PH值：

PH值表示麦芽的酸度，麦芽的PH值通常为5.90左右，当用含硫原料在加热炉直接加热时，这个值会减至5.75。PH值低使得协定糖化醪的大多数酶的活性提高，因此也得到较高的浸出率和较好的45℃哈同值，但蛋白溶解较多，现在普通采用间接加热方式，PH值会在5.85-5.90之间，测PH值应注意：(1)PH计每天使用前应进行校正，校正时的的温度与使用时的温度相差不得超过1℃，由于许多实验室没有空调，冬季、夏季温差较大，PH值测试有较大误差。(2)应该统一使用20℃恒温进行校正和测量，报出的PH值也应统一规定为20℃时的实测值，没有温度限定的PH值没有意义。

16.总酸：

与PH不同，总酸是指麦芽生产H+的总能力，它们之间的关系是

AH≒A-+H+

在这种平衡状态下，PH测定的是当时的H+浓度，而总酸测定的是这个方程式全部向正方向反应，在AH不存在的情况下的H+浓度。一般的情况下，总酸要求在1.2(0.1NHONaml数/100ml)以下,过高则啤酒的酸味过浓,而且是不正常的酸味。麦芽总酸过高主要是浸麦换水不到位，抽二氧化碳不够，在发芽中死粒过多、发芽温度过高，通风不够等造成的。

17.脆度：

脆度反映了麦芽的溶解度和酿造性能，国际上一般要求在80%以上。实验室测定时应定期检查辊距、筛网，定期进行实验室之间的对比试验，麦芽经过贮存运输，含水量不同以及皮壳厚薄不同，对检测结果有直接的影响，所以商品麦芽的验收，应视品种水分进行同比验收，生产厂家的出炉麦芽脆度分析值可作为质量证明。

18.黏度：

麦汁的黏度与溶解度和β-葡聚糖含量有关，黏度值超过1.67mpa.s，一方面表示溶解较差，另一方面意味着β-葡聚糖含量过高，黏度低于1.40mpa.s说明在β-葡聚糖很低的情况下，部分麦芽过分溶解。`一般要求小于等于1.55 mpa.s。

19.a-氨基氮：

a-氨基氮指氨基酸类低分子氮类，a-氨基氮对麦汁组成、啤酒发酵有重要意义，是酵母发酵时所需的主要氮源。影响麦芽中a-氨基氮含量的主要因素是大麦品质与特性、浸麦度、发芽温度和时间、干燥前期温度和时间。如浸麦度低，发芽前期温度过高，后期又过低，干燥前期温度高，升温过快，焙焦温度高，时间长等，都会减少麦芽中a-氨基氮的含量。一般要求150mg/100g以上。

20.糖化力：

糖化力是啤酒酿造中非常重要和指标，因此各厂都有其明确的规定，如果偏低，一是粮化时间将延长，因而导致麦汁的组成不协调;二是如果糖化的不彻底，将导致麦汁过滤困难，混浊不清，啤酒易发生混浊沉淀。糖化力低是因为原大麦本身糖化力低、蛋白质含量低、发芽时间短、发芽温度低、干燥温度高、升温过快、焙焦温度高、时间长等因素造成的。一般要求260WK以上。

21.粉状粒与玻璃质粒：

大麦经浸麦后进入水分，经发芽溶解后形成粉状粒，而没有发芽溶解，经烘干后就有可能形成玻璃质粒，在一粒麦子中发芽不彻底，有溶解的部分，有没有溶解的部分，则形成了半玻璃质粒。

玻璃质粒和半玻璃质粒的玻璃质部分在糖化发酵中很难转化为有效部分，因此人们希望这类物质越少越好。

由此可见一方面是大麦的发芽率越高越好，另一方面在发芽中叶芽伸长度越整齐越好。

22.叶芽伸长度：

叶芽伸长度分六个部分，即0、0-1/4、1/4-1/2、1/2-3/4、3/4-1、>1。从根本上说，叶芽在3/4-1这一段最好，但这是不可能的，因此人们希望在这一段的数量越多越好。>1的就意味着长出了叶芽，经烘干除根后损失掉了，直接影响着麦芽的制成率，这是麦芽厂不愿意看到的。低于这一阶段，溶解不完全对于啤酒质量和数量都有影响。如果是0则更没有意义了。

23.β-葡聚糖：

这些年这一项目越来越受到啤酒厂家的重视，原因就是麦芽中如果有大量的β-葡聚糖存在，糖化过滤将非常困难。同时人们在最近的几年中也对这一项目研究的比较突出。众所周知β-葡聚糖存在于大麦的细胞壁中，经发芽而被溶解，这就看被溶解的程度。因此，这一问题的关键第一是大麦的品种、种植的年份。第二才是发芽的工艺和操作。一般地来讲，二棱大麦比四、六棱大麦要少;粒大饱满的大麦比颗粒瘦小的大麦含量要低。

对于啤酒厂来说一般的β-葡聚糖只要低于150mg/100g，是不会受影响的。

最后，大家可以参考国家QBT 1686-2008 啤酒麦芽标准，该标准详细列明各项理化指标的检测依据，区分了什么是优级麦芽、一级麦芽、二级麦芽等等。大家应该根据自己所需去选用适合自己的麦芽原料。