Brewing Quality Control Manual Series COMBINED AND EDITED ORIGINAL VERSIONS - FEB 2016

Transcription

1 Brewing Quality Control Manual Series COMBINED AND EDITED ORIGINAL VERSIONS - FEB 2016 This presentation sees the combination of three short articles in an original (though revised) format. The series was picked up by the Scandinavian Brewer s Review and continued with Quality of Process articles: Milling, Mashing and Lautering to date. The raw materials topics: water, malt (adjuncts) and hops are combined here essentially as they were before the SBR published them. The decision to reproduce them in this format comes on the heels of a new SBR article (they now publish these notes first) which covers important flavor notes arising from malt and hops or that are influenced by the brewing liquor quality and ionic composition. Water, malt (sometimes adjuncts) and hops must all be considered as starting points for quality beer. (1): Water Water. Much has been written and said about the strict demands for the quality of the water used for brewing in general and for brewing classic beer styles. As this is a complex topic only a few key points will be made here on the subject. Suffice it to say water plays a key role in the physiology of malting and in the biochemistry and chemistry of mashing, in wort boiling and in fermentation - thus impinging on many influences impacting the character of the final beer. Starting with any potable quality water (governed by local and international water authority regulations) several purification protocols and methods and simple adjustments of salts (mineral ions) can be undertaken to ensure a good start in brewing quality beer and making the intended style of beer. In general water should be free of microbes, iron (keep below 0.5 mg/l), manganese (keep below 0.3 mg/l), suspended matter, pesticides, other organic compounds, odorant chemicals which will cause flavor taints, and nitrates (to help prevent nitrosamine formation). What tests can you do and which processes should you implement and understand? Simply taste and smell the water. It should be free of color, odor, particulate matter and taste. Understand the mineral composition of the required style of beer to be produced (see many works on this matter including, Water in Brewing in the EBC Manual of Good Practice series, 2001). Alkalinity of water expressed as It starts with the raw materials - series. (1): Water equivalents of calcium carbonate should be less than 100 ppm. (mg/l) and better if less than 50 ppm. to start with for subsequent manipulation of mineral ions in order to prevent undesirable mash ph later on. A low ph (recommended range between ph of 6.0 and 7.5) of brewing water, helping to ensure a low wort ph, will increase total soluble nitrogen and free amino nitrogen (yeast nutrients), increase extract yield, increase wort run-off rate, lead to decreased extraction of harsh tannins and hop bittering compounds and increase fermentability of the final wort. Calcium ion concentration, largely added from brewing water (though ppm. comes from malt), of mg/l (according to beer type) will help reduce ph, stabilize and stimulate enzymes during mashing and, importantly for quality of final product, will precipitate oxalates preventing haze formation and gushing. It is not widely understood that about 50% of calcium is lost from start to finish in brewing processes much being lost in the mash bed itself (which is a great ion-exchanger!). This needs to be accounted for up front and it is generally held that ppm. Calcium in the final beer is good for overall stability and quality. Other ions play positive and negative roles (the latter mainly on off-flavor generation or taints) but, apart from zinc and iron, these are not discussed at length here (see table 1 on p2. for recommended levels). Iron levels should be low to avoid incomplete saccharification, haze formation (metallic hazes), inhibition of yeast, impaired beer color, flavor and colloidal stability, oxidation issues and discoloration of foam. Zinc in trace amounts is a yeast nutrient, stimulates fermentation and limits H 2 S formation. At higher levels it can inhibit enzymes, yeast growth and catalyze beer oxidation reactions leading to haze and flavor quality issues. Mineral ions were considered here from the viewpoint of the effect on quality of final beer through the numerous processes on the way to finished product. The information should be reviewed when considering quality issues at each step in the brewing process but many other substances can impact efficiency and quality of beer production. The World Health Organization provides frequently updated guidelines and the book Water in Brewing EBC Manual of Good Practice (2001) covers more on microbial load, pesticides, herbicides, organic compounds, ions and other toxic substances which brewers ought to be aware of. See also Monograph XIV European Brewery Convention: EBC Symposium Water in the Brewing Industry (1988). However, following reports obtained from the local water authority or lab specializing in water chemistry and microbiology, together with an understanding of water purification systems, along with simple mineral adjustment calculations will generally be sufficient to ensure a good start and continued positive impact throughout the brewery process towards a high quality and consistently produced beer. Recommended for brewing salt adjustments is... (see page 2)

2 continued from page 1... Glenn Tinseth s water calculator (some minor though not significant errors) available from the Probrewer website. Lager beers are best made with the use of soft waters (low mineral content and low in carbonates) to bring out the more delicate flavors of this class. Reduction in ph is important (see above) but calcium ion levels are not as important as for other styles due to the use of lightly kilned malts. For Pale Ales and Bitters bicarbonates should be below 60 ppm. and the calcium concentration above 125 ppm. Sulfates higher than chlorides to enhance bitterness and hop flavor. Milds and Stouts require carbonates to be less than 60 ppm. and calcium at 75 ppm. for milds and 30 ppm. for stouts. A full understanding of bicarbonate, carbonate and hydroxyl ions dealing with alkalinity are not presented here but a basic understanding of water chemistry and mineral ion adjustment will aid in quality considerations at this raw materials stage of operations. References: (Water chemistry is an involved and complex topic and many books - an exhaustive list - have been published on water and water quality - including waste water but a few key volumes for brewers are included here). Water in Brewing (No 1 in the European Brewery Convention Manual of Good Practice Series) (2001) EBC and Fachverlag Hans Carl. ISBN: EBC Symposium: Monograph-XIV: Water in the Brewing Industry September Hans Carl. ISBN: Recent: The MEBAK (Brewing Commission) has made available in English a classic volume on Water Chemistry for the Laboratory. [Contact us for details]. For guidance on adjusting water we refer the reader to the Probrewer.com website and Glenn Tinseth s water calculator. There are a couple minor errors in that calculator (based on water of hydration of salts) but it is the most useful calculator out there and gives reliable results for any scale of brewing operation. Again consult with us for further guidance on its use if desired. See: Follow us: Twitter, LinkedIn, Facebook and Google+ Coming next >Part 2: Malted Barley. Table 1 appears below. Table: Recommended concentrations of some ions for brewing (in water & levels) some (negative) quality issues briefly mentioned. Calcium: mg/l according to beer type see text for roles mainly positive. Along with magnesium a primary contributor to water hardness. Magnesium: Avoid concentrations above 30 mg/l Excess can cause bitter flavor. Along with calcium a primary contributor to water hardness. Sodium: Maximum concentration is about 150 mg/l. Above this > sour and salty perceptions. Potassium: Potassium is mainly from malt so water levels rarely considered to be significant. High levels saline/salty. Iron ferric (Fe 3+ and ferrous Fe 2+ ): Maximum recommended level Fe 2+ and Fe 3+ in brewing water 0.2 mg/l see text for roles mainly negative! Causes taste, discoloration issues and contributes to hardness. Copper: Keep below 0.1 mg/l in brewing water. Below 1 mg/l colloidal/flavor instabilities. Above 10 mg/l inhibits enzymes and is toxic to yeast. Zinc: Between mg/l recommended range in brewing water. See text for positive and negative roles! Manganese: Keep below 0.05 mg/l high levels impact colloidal stability. Causes taste, discoloration issues and contributes to hardness (though not as potently as for iron). Sulfate: Between 10 and 250 mg/l. Gives beer drier/more bitter palate but can lead to SO 2 and H 2 S formation. Chloride: Maximum 150 mg/l. Aids beer body/palate fullness (can reduce palatability) but can inhibit yeast flocculation and fermentation at higher levels. Toxic to yeast above 300 mg/l. Stress corrosion issues with stainless steel. Contributes to permanent hardness. Nitrate and Nitrite: Max. concentration nitrite 0.1 mg/l/nitrate 50 mg/l. Nitrite can indicate contaminated water (wastewater) and is toxic to yeast. Nitrates can come from malt and hops final content in beer should not exceed 50mg/L. Silicate: These ions usually originate with malt. May cause haze in combination with calcium ions. Above 40 mg/l fermentation issues, haze formation during Pasteurization. Phosphates: positive roles in general but max concentration recommended at 1.0 mg/l. Fluoride: Max. concentration fluoride ions 1.5 mg/l though up to 10 mg/l regarded as exerting no adverse effects on brewing processes. H 2 S (Hydrogen sulfide). Avoid affects taste and odor. Found in groundwater and is produced by bacterial metabolism of sulfur-containing minerals or decomposition of organic matter. Detect via aromatic qualities sewer-drains, rotten eggs.

3 Brewing Quality Control Manual Series This note sees the second article in the Brewing Quality Control Series from Brewing and Distilling Analytical Services, LLC. The Raw Materials set covers three topics: water, malt and hops and provides essential guides to examination of the quality of raw materials to help ensure total quality production of beer. Given enough interest in this first series the topic will continue in looking at all aspects of the brewing process from milling to final packaged goods. Material will be drawn from the brewing literature but is directed by the titles in the EBC Manual of Good Practice series from Europe. Questions and requests for further materials to enhance each topic are welcomed and the series can only become better through your valued and valuable input: direct enquiries please to It starts with the raw materials - series. (2): Malt (Malted Barley) {Essentially for Base Malts} Water, malt (sometimes adjuncts) and hops must all be considered as starting points for quality beer. (2): Malt Malt. Malted Barley. Brewers don t usually have any control over malting but that is also where it starts for producing quality beer along with careful hop selection. Malted barley provides the first point of contact for optimization of brew house operations. Thus, brewers can help to start the quality process and ensure consistent beer production by procuring good malt (and adjuncts for specialty beers) from a reputable maltster and understanding the lot information which should be provided with every batch. A few simple tests along with careful storage and handling will go a long way in ensuring quality of raw material for a quality beer. Beers which differ in taste, color, aroma, mellowness and head retention start with malts produced by different processes, an understanding of which comes from knowing the basis of malting technology (See EBC Manual of Good Practice: Malting Technology, 2000 ISBN: , Fachverlag Hans Carl, for more detail). In addition to specifications mentioned in the Table (below): malt must be sufficient in fermentable carbohydrate (aids in wort production) and have good fermentability (aids in fermentation). Malts must have good color and flavor, colloidal stability, foam potential, flavor stability and wholesomeness all good requirements for beer quality. What tests can you do and which processes should you implement and understand? Simply examine the malt samples should be free from other seeds and other dirt and matter (less than 1% by weight). Grains should not show damage (broken and split grains) and should not be green and show no signs of microbial activity or spoilage. Aroma should be fresh. Malt should be free of fungicides, pesticides and growth regulators. The endosperm should be mealy (scratch like chalk) rather than be hard and steely. Crush and taste the grains to ensure clean and appropriate flavor and no off flavors or taints. Specific details for specialty malts may be found in the EBC Manual of Good Practice: Malting Technology (2000). Malts should be free of mycotoxins (more prevalent during fungal attack during wet growing conditions) which are toxic carcinogens, can reduce yeast growth and can be responsible for gushing. Limits are in place and more stringent in Europe. Nitrosamines also carcinogens should be low (current limits between 0.2 and 0.5 mg/kg for beer). These were more of an issue in the past but exports to Europe may demand information on nitrosamines. Details of their generation can be found in the aforementioned EBC Malting Technology manual. The table (on page 2) provides brief details pertaining to desired quality attributes of base malts but your malt supplier should be able to explain other quality terms on their lot specification sheets. [Table 1 appears below.] A particularly cogent discussion - Understanding Malt Analysis Sheets was presented by the late Greg Noonan in the 1997 Brewer s Market Guide as published by Brewing Techniques Magazine. This issue was dedicated to Malt and several other informative articles are to be found therein. Unlike for the Water Topic more information appears in the Table here on malt quality and attributes to look for. For more information, or to comment, please contact us: gspedding@alcbevtesting.com. See our website: com and our two blogs related to brewing and distilling matters: and: com/ & Follow us on LinkedIn, Facebook, Google+ and Twitter. Coming next >Part 3: Hops.

4 Table. Some general requirements Typical parameters of base malts and brief explanation of terms. [Note mg/l = ppm.] Assortment (through sieves) Mostly intact grains required. Homogeneity (aids in milling). Plump (7/64 + 6/64) >75%, Through (Thru 5/64) <3%. Ranges on each screen can vary somewhat by barley variety and sometimes crop year, but the over plump and thin content is most important. Bushel weight lbs/bushel for 2 row malt. Seek assortment information also for intactness of grains. Friability, % % for both 2 row and 6 row malted barley (aids in milling). Percentage friability is a good index of modification and suitability of malt for brewing. Less than 78-80% indicator of under-modification and is undesirable. Moisture, % - 4.5% (for both 2-row and 6-row should fall below 5%). Wet malt ( moisture >10%) is prone to microbial attack, staling and reduces yields of extract based on poor milling etc. Slack or staling malt may be seen at >6.5% moisture and this leads to the milling issues and reduced extract yields. Storage should be designed to prevent moisture uptake and malt is typically supplied in nonmoisture barrier bags. A low humidity storage facility is best for finished malt storage along with careful management of ordering and use of malt. Extract (Laboratory values) in EBC terms as is % w/w 77.4%/dry basis 81.0%. Fine and coarse extract difference % w/w - 1.9%. It is suggested that a fine/coarse difference of < 1.5% is indicative of a well-modified malt, however, it is a highly variable quality and is in-fact not the best representation of modification*. Actual brew-house extracts will depend on factors such as Mill settings. See Milling Section. Dry basic (DB) extract on base malt in fact ranges from 79-82% (76-79% as is). Two-row varieties often have a higher extract content that six-row varieties due to differences in protein content (see below). * Wort viscosity, friability, and the ST ratio (see above & below) are much better indicators of modification than the F/C difference. Saccharification time Under 10 minutes. Ease of conversion aids in mashing. Typically tested by the iodine reaction in the brew house but quantitative starch assays are available which show the amounts of starch remaining even after a negative for starch plate test with iodine. If the plate test shows conversion (assuming good iodine stock) that should be good enough for brewing. The maltsters value is the valid guide here. Fermentability, Apparent attenuation, % %. Indicates suitable and available extract for yeast fermentability. Alpha (a) amylase enzyme Dextrinizing Units 30-70DU. Contributes to the diastatic power (DP) of malt. Alpha amylase levels in 2 row and 6 row base malts are generally in the middle of this range, around 45-50DU. Alpha amylase is a key enzyme in the breakdown of starches during mashing. Protein content and extent of modification can both correlate well to alpha amylase levels. Diastatic Power (Windisch-Kohlbach units) 250. A more global measure of the starch hydrolyzing enzymes mainly a-amylase and b-amylase. Not usually an issue for all malt brewing. Most US maltsters report this in Degree Lintner. Typical range: Lintner. ph (measured in laboratory Congress worts) High 5 s to 6.0. Mash-in ph ideally adjustable with CaCl 2 and CaSO 4 mash salts. [See water and mashing sections.] Wort Color: 0 EBC 2.7 (Range base malts: L (Lovibond) SRM) [Boiled Wort Color: 0 EBC 5.5] Nitrogen/Protein content. Nitrogen, dry basis, % Relates to protein, peptides and amino acids in wort (based on nitrogen percentage of protein constituents) See Protein (more usually specified and understood than the nitrogen %) and FAN. Protein: Total protein ranges for malt usually 11-14%, with 2 row lower end and 6 row higher end. (See Kohlbach-S/T Index) [% Total N x 6.25 = % Protein] Kohlbach Index, S/T, % Typically (middle at ca. 40.5). The ratio of total soluble nitrogen to the total nitrogen of malt. Also known as the S/T (soluble to total protein) ratio on specification sheets. A measure of the soluble protein in malt. The S/T or Kolbach index is regarded as one of the best measures of modification (look for in the high 30 s to mid-40 s) as it is a consistent analysis with low test variability. Over modified malt (i.e. with a high S/T) may have increased malting losses, which may result in lower extract yields for brewers. Over 49 is suggested by some to be a potential for beta-glucan issues but to avoid that - 45 should be considered as a cut-off based on the above criteria. Free Amino Nitrogen FAN, ppm. 150 (generally optimal for normal strength worts). Important nutrient source for yeast. High Molecular Weight b-glucan, ppm High molecular weight glucans pose viscosity/filterability issues. According to one major malt supplier b-glucan values (if expressed on specification sheets) at less than 140 ppm. no problems and showing evenly modified malt. b-glucanase, IRVU (viscosity units) 550. Enzymes producing more soluble glucans and glucose leading to reduced viscosity and stuck or poorly filterable mashes. See Kohlbach Index, S/T ratio and friability for guidance if viscosity information not available. Viscosity (cp, centipoise). Typically recommended at 1.56 cp (or mpa.s). A lab wort over 1.75 cp will not run off well during sparging. Dimethyl sulfide precursors (known as SMM), mg/kg 4.0. DMS in beer principally from DMS precursors in malt but can come from bacterial contamination. Lighter malts are higher in SMM. Nitrosamines, mg/kg See text. FDA regulation: <10 ppb. Malt, <5 ppb. Beer. Polyphenols polymers of plant phenols. Large molecular weight undesirable (implicated in beer haze) but low molecular weight tannoids prevent oxidative damage and enhance beer flavor stability. Data not usually provided by the maltster. Tannoids are precipitable by PVP (polyvinyl pyrrolidone). Gary Spedding for BDAS, LLC, June 2012.

5 Brewing Quality Control Manual Series This note sees the third article in the Brewing Quality Control Series from Brewing and Distilling Analytical Services, LLC. The Raw Materials set covers three topics: water, malt (adjuncts) and hops and provides essential guides to examination of the quality of raw materials to help ensure total quality production of beer. Given enough interest in this first series the topic will continue in looking at all aspects of the brewing process from milling to final packaged goods. Material will be drawn from the brewing literature but is directed by the titles in the EBC Manual of Good Practice series from Europe. Questions and requests for further materials to enhance each topic are welcomed and the series can only become better through your valued and valuable input: direct enquiries please to It starts with the raw materials - series. (3): Hops and Hop Extracts Water, malt (sometimes adjuncts) and hops must all be considered as starting points for quality beer. (3): Hops Hops and hop extracts. Hops should be fresh at purchase with declared alpha acid, beta acid content and sometimes a Hop Storage Index value (rough guide to how well they age). However, they do lose bittering potential if not stored correctly and, if tested at any stage by a laboratory for alpha and beta acids, equations exist to predict what the alpha-acid value was when 100% fresh (unless they are very old and much degraded). Such tests enabled the brewer to determine the required increases in hop additions to maintain consistency of bitterness. Bittering units measured in the lab are not the same as tasted (organoleptic) bitterness and alpha acids account for only about 70% of the reading. Beta-acids convey a harsher bitterness. Perceived bitterness is influenced by hop oil aromatics just now becoming better understood and researched but the topic is complex. The hop storage index shows that for each 0.01 increase in value reflects about 1% loss in alpha acid. Hops should be supplied in low-oxygen packages (vacuum packed) and kept at low temperature. Open and quickly reseal and store appropriately to maintain freshness. If old but suitably stored have a lab measure the key parameters mentioned above. If using specialty hop products (liquid extracts) for bittering and or aroma understand the properties of such products for optimal use. A comprehensive discussion of hops and hop products can also be found in the EBC Manual of Good Practice: Hops and Hop Products, (1997) published by Fachverlag Hans Carl. ISBN: What tests can you do and which processes should you implement and understand? Ask for samples and perform a hop inspection including a rub. Break open the package and rub the hops to disintegrate and allow the hop resins to show their character. Sniff and feel the hops for quality. Using hop pellets? if so crumble a few and see and smell for freshness and aromatic qualities look at the color and feel for over moist (wetcrumble) or over dry brittle pellets. Whole cone hops look at the color of bracts and the lupulin glands (bright yelloworange?), moisture (spongy or crumbly do they spring-back?). Ensure no seeds, leaves or other non-hop or extraneous matter look at cone integrity and look for damage by insects, molds or weather, (discoloration of leaves or telltale spots). Finally evaluate the aroma (and make hop teas via boiling a portion in a sugar solution to examine flavor). Unfortunately there is not yet a hop-variety flavor wheel to aid in understanding the vast array of flavor notes that can be provided by hop usage but the Table below gives some base descriptors for this aspect of beer flavor. Most hop producers also have comprehensive guides to hop varieties, qualities, alpha and beta acid content (bittering potential) and aroma (oilcontent) characteristics. More information is also to be found in Brewing Chemistry and Technology in the Americas, Ed. Peter W. Gales, ASBC, 2007, (Chapter 6), ISBN: Issues with respect to the type of hops used by brewers, point of addition of hops in the brewing process and the desired effects (bitterness, aroma and foam enhancement) along with hop utilization (extraction efficiency for alpha acids) and bitterness losses during brewing will be covered in other articles in the extended series. Typically European Lagers aim for IBU s (International bitterness units); UK Ales IBU s; Lagers in the USA IBU s; Australian Lagers IBU s and German Pilsners IBU s. It becomes increasingly difficult to solubilize and isomerize alpha acids (covered in the section on Wort Boiling and Clarification) and more expensive to push the boundaries on hop bitterness as practiced by many US craft brewers and after IBU s (depending upon beer strength and other parameters including hop aromatics) sensory fatigue sets in and thus it is not a trivial matter to best understand the requirements or the limits of hop bitterness. These topics will be dealt with again in the brewing processes portion of this quality series. Coming soon > Brewing Processes - from start to finish. This next section will be available upon request only. The Raw materials articles were direct open source but to judge popularity we feel the need to restrict the next series sets to interested individuals specifically requesting copies. A Table of general hop flavor characteristics appears on the next (or back) page.

6 continued from page 1... Coming soon > Brewing Processes - from start to finish. This next section will be available upon request only. The Raw materials articles were direct open source but to judge popularity we feel the need to restrict the next series sets to interested individuals specifically requesting copies. Starts with Milling. Table 1 appears below: Aroma qualities of hops (use of the multitude of varieties of hops to convey varied and unique flavor profiles). See also: Using Hops (The Complete Guide to Hops for the Craft Brewer), Mark Garetz, (1994) Hop Tech Publications, ISBN And for latest in hop flavor: Hop Flavor and Aroma, Ed. Thomas H. Shellhammer, (2009) -ASBC-MBAA Publications, ISBN: Tom has also recently published info. on hop bitterness and utilization. Very solid information on this topic from Oregon. For more information, or to comment, please contact us: gspedding@alcbevtesting.com. See our website: com and our two blogs related to brewing and distilling matters: and: com/ & Follow us on LinkedIn, Facebook, Google+ and Twitter. Table. Aroma qualities of Hops (A general profile of flavors conveyed by different hops and fresh and aged hops.) The descriptors will be presented in hop profiles by any reputable hop supplier. The terms may also form the basis for a hop essential oil-aromatic flavor wheel. General Profile Term Fruity American Herbal Floral Herbaceous Resinous Spicy Noble Off -Old/Aged/Oxidized Flavor Note descriptor-terminology Citrus, berry, tropical, pear, apricot. Grapefruit (rind) -, citrusy, tomato leaves, juniper and catty (blackcurrant). Minty, dried culinary herbs, tobacco or black tea. Roses, geranium, chamomile and coriander. Grassy, hay-like, vegetal and green. Balsam, piney, lacquer-like (furniture polish) and mineral (engine) oil (in high alpha hops). Black pepper, allspice and cinnamon. Cedarwood/sandalwood, curry, woodsy, complex spice. Onion/garlic cheesy/rancid, musty and woody (pencil shavings). Older/late harvested hops can show these and other sulfury notes.