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[[Category: | [[Category:Wort production]] [[Category:Equipment and maintenance]] | ||
[[File:Grain-milled.png|thumb|Milled grain. Photo by Bryan Rabe.]] | [[File:Grain-milled.png|thumb|Milled grain. Photo by Bryan Rabe.]] | ||
[[Grain]] consists mainly of [[starch]] granules (endosperm) inside a husk. Before the [[mashing|mash]], grain must be mechanically crushed using a mill. The crushing process breaks open the husks, exposing the starch, and also cracks the starch into smaller bits, increasing the surface area exposed to water and [[enzymes]] during mashing.<ref name=mostra>Mosher M, Trantham K. [[library|''Brewing Science: A Multidisciplinary Approach.'']] 2nd ed. Springer; 2021.</ref> The crushed grain is referred to as ''grist''. In general, the crush quality affects the [[mashing|mashing process]], including [[starch|saccharification]] time, [[lautering]], [[efficiency]], [[fermentation]], as well as the color, taste, and overall character of the beer.<ref name="Kunze">Kunze W. Wort production. In: Hendel O, ed. [[Library|''Technology Brewing & Malting.'']] 6th ed. VBL Berlin; 2019:203–218.</ref><ref name="Mousia">Mousia Z, Balkin RC, Pandiella SS, Webb C. [https://www.sciencedirect.com/science/article/pii/S0032959203004400 The effect of milling parameters on starch hydrolysis of milled malt in the brewing process.] ''Process Biochem.'' 2004;39(12):2213–2219.</ref> | [[Grain]] consists mainly of [[starch]] granules (endosperm) inside a husk. Before the [[mashing|mash]], grain must be mechanically crushed using a mill. The crushing process breaks open the husks, exposing the starch, and also cracks the starch into smaller bits, increasing the surface area exposed to water and [[enzymes]] during mashing.<ref name=mostra>Mosher M, Trantham K. [[library|''Brewing Science: A Multidisciplinary Approach.'']] 2nd ed. Springer; 2021.</ref> The crushed grain is referred to as ''grist''. In general, the crush quality affects the [[mashing|mashing process]], including [[starch|saccharification]] time, [[lautering]], [[efficiency]], [[fermentation]], as well as the color, taste, and overall character of the beer.<ref name="Kunze">Kunze W. Wort production. In: Hendel O, ed. [[Library|''Technology Brewing & Malting.'']] 6th ed. VBL Berlin; 2019:203–218.</ref><ref name="Mousia">Mousia Z, Balkin RC, Pandiella SS, Webb C. [https://www.sciencedirect.com/science/article/pii/S0032959203004400 The effect of milling parameters on starch hydrolysis of milled malt in the brewing process.] ''Process Biochem.'' 2004;39(12):2213–2219.</ref> | ||
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* '''Control''' - Adjusting the gap allows you to tailor the crush to your own system and maximize [[efficiency]]. | * '''Control''' - Adjusting the gap allows you to tailor the crush to your own system and maximize [[efficiency]]. | ||
* '''Consistency''' - The crush size may be inconsistent with pre-milled grain. | * '''Consistency''' - The crush size may be inconsistent with pre-milled grain. | ||
* '''Grain conditioning''' - Milling | * '''Grain conditioning''' - Milling on site gives you the option to condition your grain (see below). | ||
* '''Cost savings''' - A personal grain mill eventually pays for itself because A) you avoid a milling fee and B) you can buy grain in bulk. | * '''Cost savings''' - A personal grain mill eventually pays for itself because A) you avoid a milling fee and B) you can buy grain in bulk. | ||
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[[File:Knurled-rollers.jpg|thumb|right|Knurled rollers on a 3-roller mill (bottom view)]] | [[File:Knurled-rollers.jpg|thumb|right|Knurled rollers on a 3-roller mill (bottom view)]] | ||
*'''3-roller vs 2-roller''' - In a 3-roller mill, the grain is pre-crushed in the gap between the top two rollers, and then the grain flows into the gap between the drive roller and bottom roller, crushing it further. The top gap is fixed at around 0.060–0.070" which easily pulls in both wheat and barley, providing superior feed, and softening the starch without tearing up the husk.<ref name="monster">[https://www.monsterbrewinghardware.com/store/pc/FAQs-d2.htm FAQs.] Monster Brewing Hardware. Accessed May 2020.</ref> The lowered husk damage aids in lautering among other things (see below). The double crush also more fully separates the husk from the starch. The downsides to 3-roller mills are that more power (torque) is typically required to drive them and they are generally more expensive. 2-roller mills are more budget friendly. | *'''3-roller vs 2-roller''' - In a 3-roller mill, the grain is pre-crushed in the gap between the top two rollers, and then the grain flows into the gap between the drive roller and bottom roller, crushing it further. The top gap is fixed at around 0.060–0.070" which easily pulls in both wheat and barley, providing superior feed, and softening the starch without tearing up the husk.<ref name="monster">[https://www.monsterbrewinghardware.com/store/pc/FAQs-d2.htm FAQs.] Monster Brewing Hardware. Accessed May 2020.</ref> The lowered husk damage aids in lautering among other things (see below). The double crush also more fully separates the husk from the starch. The downsides to 3-roller mills are that more power (torque) is typically required to drive them and they are generally more expensive. 2-roller mills are more budget friendly. | ||
*'''Bearings vs bushings''' - Sealed ball bearings generally require no maintenance and can have a significantly longer lifespan than bushings, particularly if you drive the mill with a pulley.<ref>[https://www.homebrewtalk.com/threads/grain-mill-recomendations.662727/post-8529641 Grain mill recomendations.] | *'''Bearings vs bushings''' - Sealed ball bearings generally require no maintenance and can have a significantly longer lifespan than bushings, particularly if you drive the mill with a pulley.<ref>[https://www.homebrewtalk.com/threads/grain-mill-recomendations.662727/post-8529641 Grain mill recomendations.] Homebrew Talk website. 2019. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/quality-corona-hand-crank-mill.645349/post-8224674 Quality corona/hand-crank mill?] Homebrew Talk website. 2018. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/tell-me-about-grain-mills.666252/post-8598698 Tell me about grain mills.] Homebrew Talk website. 2019. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/grain-mill-recomendation.672926/post-8734778 Grain mill recomendation.] Homebrew Talk website. 2019. Accessed 2020.</ref> On the other hand, bushings have more friction and may wear over time, such that they will need to be replaced at some point.<ref>Layosa C. [https://blog.misumiusa.com/introduction-to-working-with-linear-bushings-bushings-vs-bearings/ Introduction to working with linear bushings: bushings vs. bearings.] Misumi website. 2016. Accessed 2020.</ref><ref>[https://youtu.be/fJVGlvZQvGk Ball Bearings vs Bushings.] ServoCity on YouTube. 2017. Accessed 2020.</ref> Therefore we recommend a mill with sealed ball bearings. However, bushings are still an acceptable option when using a direct drive system such as a drill. Bushings may benefit from periodic cleaning and lubrication with a drop of food-grade mineral oil; check with the manufacturer.<ref name="LOB-1069">[http://www.themodernbrewhouse.com/forum/viewtopic.php?f=18&t=1069 Choosing a malt mill.] The Modern Brewhouse website. 2018–2020. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/monster-mill-problems.102809/post-1141303 Monster mill problems.] Homebrew Talk website. 2009. Accessed 2020.</ref> | ||
*'''Roller material''' - For most brewers, hardened steel is the best option for roller material due to its durability.<ref>[https://www.reliance-foundry.com/blog/carbon-steel-versus-stainless-steel Carbon steel vs stainless steel.] Reliance Foundry. Accessed June 2020.</ref> However, stainless steel has better protection against corrosion (although it is also more expensive). If you live in a damp or coastal region, stainless might be a good option.<ref name="bison">Green T. [https://bisonbrew.com/grain-mill/ The best grain mills for homebrewing.] Bison Brew. 2020. Accessed 2020.</ref><ref>[https://www.monsterbrewinghardware.com/store/pc/3-Roller-Homebrew-Grain-Mill-p86.htm 3 roller homebrew grain mill.] Monster Brewing Hardware. Accessed June 2020.</ref> | *'''Roller material''' - For most brewers, hardened steel is the best option for roller material due to its durability.<ref>[https://www.reliance-foundry.com/blog/carbon-steel-versus-stainless-steel Carbon steel vs stainless steel.] Reliance Foundry. Accessed June 2020.</ref> However, stainless steel has better protection against corrosion (although it is also more expensive). If you live in a damp or coastal region, stainless might be a good option.<ref name="bison">Green T. [https://bisonbrew.com/grain-mill/ The best grain mills for homebrewing.] Bison Brew. 2020. Accessed 2020.</ref><ref>[https://www.monsterbrewinghardware.com/store/pc/3-Roller-Homebrew-Grain-Mill-p86.htm 3 roller homebrew grain mill.] Monster Brewing Hardware. Accessed June 2020.</ref> | ||
*'''Roller diameter''' - Larger diameter helps the grain feed through the rollers.<ref name="Kunze"/><ref name=mashing>Evans E. [[Library|''Mashing.'']] American Society of Brewing Chemists and Master Brewers Association of the Americas; 2021.</ref> | *'''Roller diameter''' - Larger diameter helps the grain feed through the rollers.<ref name="Kunze"/><ref name=mashing>Evans E. [[Library|''Mashing.'']] American Society of Brewing Chemists and Master Brewers Association of the Americas; 2021.</ref> | ||
*'''Knurled vs fluted rollers''' - Roller morphology has an important effect on the crush by reducing damage to the husk. Modern ''commercial'' mills always have fluted rollers.<ref name=Mousia/><ref name=Kunze/><ref name=hob11>Miedl-Appelbee M. Brewhouse technology. In: Stewart GG, Russell I, Anstruther A, eds. [[Library|''Handbook of Brewing.'']] 3rd ed. CRC Press; 2017.</ref> On the other hand, most home brew mills have rollers with a diamond knurling pattern, which is necessary to improve the grain feed through small diameter rollers. A few home brew mills with relatively larger rollers (e.g. MattMill and Ss Brewtech) have a fluted morphology. However, the fluting pattern on these is completely different than commercial mills,<ref name=Kunze/> so it is unclear whether the fluting provides any benefit over knurling for home milling. | *'''Knurled vs fluted rollers''' - Roller morphology has an important effect on the crush by reducing damage to the husk. Modern ''commercial'' mills always have fluted rollers.<ref name=Mousia/><ref name=Kunze/><ref name=hob11>Miedl-Appelbee M. Brewhouse technology. In: Stewart GG, Russell I, Anstruther A, eds. [[Library|''Handbook of Brewing.'']] 3rd ed. CRC Press; 2017.</ref> On the other hand, most home brew mills have rollers with a diamond knurling pattern, which is necessary to improve the grain feed through small diameter rollers. A few home brew mills with relatively larger rollers (e.g. MattMill and Ss Brewtech) have a fluted morphology. However, the fluting pattern on these is completely different than commercial mills,<ref name=Kunze/> so it is unclear whether the fluting provides any benefit over knurling for home milling. | ||
*'''Drive shaft''' - A 1/2" integrated drive shaft is the most durable. If you have a drill that you plan to use for milling, verify that it can fit on the drive shaft for the mill you want to purchase. | *'''Drive shaft''' - A 1/2" integrated drive shaft is the most durable. If you have a drill that you plan to use for milling, verify that it can fit on the drive shaft for the mill you want to purchase. (See [[Milling#Driving the mill|Driving the mill]] below) | ||
*'''Hopper size''' - Hopper size is a matter of convenience and budget. It is most convenient to add the grain to the hopper all at once, however it doesn't hurt anything if you need to pause partway through milling in order to fill the hopper with more grain. Portability, weight, and storage space should be also be taken into account. Some mills have optional hopper extensions to purchase, or you can make a hopper extension yourself. | *'''Hopper size''' - Hopper size is a matter of convenience and budget. It is most convenient to add the grain to the hopper all at once, however it doesn't hurt anything if you need to pause partway through milling in order to fill the hopper with more grain. Portability, weight, and storage space should be also be taken into account. Some mills have optional hopper extensions to purchase, or you can make a hopper extension yourself. | ||
*'''Throughput rate''' - Differences in roller length and how fast the rollers feed grain is generally negligible for home brewers and not something that needs to be considered. Throughput depends largely on drive speed (RPM) and not the particular mill characteristics. | *'''Throughput rate''' - Differences in roller length and how fast the rollers feed grain is generally negligible for home brewers and not something that needs to be considered. Throughput depends largely on drive speed (RPM) and not the particular mill characteristics. | ||
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!Where to purchase | !Where to purchase | ||
|- style="vertical-align:top;" | |- style="vertical-align:top;" | ||
|[[File:Star-6-16.png|right]]Cereal Killer, <br/>Kegco 2, <br/>Hullwrecker, <br/>Malt Muncher 2 <br/>(All the same) | |[[File:Star-6-16.png|right|alt=star]]Cereal Killer, <br/>Kegco 2, <br/>Hullwrecker, <br/>Malt Muncher 2 <br/>(All the same) | ||
|Knurled 1.25" x 5" hardened steel | |Knurled 1.25" x 5" hardened steel | ||
|Sealed ball bearings | |Sealed ball bearings | ||
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!Where to purchase | !Where to purchase | ||
|- style="vertical-align:top;" | |- style="vertical-align:top;" | ||
|[[File:Star-6-16.png|right]]Kegco 3, <br/>Malt Muncher 3 <br/>(same) | |[[File:Star-6-16.png|right|alt=star]]Kegco 3, <br/>Malt Muncher 3 <br/>(same) | ||
|Knurled 1.5" x 6" hardened steel | |Knurled 1.5" x 6" hardened steel | ||
|Sealed ball bearings | |Sealed ball bearings | ||
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*{{MB|ultimill-ultimate-grain-mill}} | *{{MB|ultimill-ultimate-grain-mill}} | ||
|} | |} | ||
[[File:Star-6-16.png]] = Editor's Pick | [[File:Star-6-16.png|alt=star]] = Editor's Pick | ||
Crankandstein has a few barebones mills that are suited to the DIY | Crankandstein has a few barebones mills that are suited to the DIY-inclined brewer. You can get a basic mill and mount it in any mill housing design of your choice. They offer a [https://www.crankandstein.net/index.php?main_page=product_info&cPath=7&products_id=11 2-roller] mill, [https://www.crankandstein.net/index.php?main_page=product_info&cPath=7&products_id=13 3-roller] mill, and a [https://www.crankandstein.net/index.php?main_page=product_info&cPath=6&products_id=9 2-roller mill that can also crush corn]. All of these have knurled hardened steel rollers and bronze bushings. | ||
=== Mills to avoid === | === Mills to avoid === | ||
*'''The Barley Crusher''' - It has soft rollers and soft/cheap bronze bushings, which lead to relatively frequent problems and a short product lifespan.<ref>[https://www.homebrewtalk.com/threads/grain-mill-stopped-working.654248/ Grain mill stopped working.] | *'''The Barley Crusher''' - It has soft rollers and soft/cheap bronze bushings, which lead to relatively frequent problems and a short product lifespan.<ref>[https://www.homebrewtalk.com/threads/grain-mill-stopped-working.654248/ Grain mill stopped working.] Homebrew Talk website. 2018. Accessed 2020.</ref> Their customer service is also very poor.<ref>[https://www.homebrewtalk.com/threads/barley-crusher-customer-service.297352/ Barley Crusher - customer service????] Homebrew Talk sebsite. 2012–2018. Accessed 2020.</ref> | ||
*'''Suspicious budget mills''' such as the [https://www.vevor.com/products/electric-grain-mill-barley-grinder-malt-crusher-hold-up-to-11lbs-crushing-dy-368 motorized] and [https://www.vevor.com/products/grain-mill-barley-grinder-malt-crusher-3-roller-wheat-home-brew-food-industry 3-roller] mills at Vevor - These cheap mills have a number of {{amazon|B07D1Y51WT|bad reviews}} and generally don't have a strong track record, so we don't recommend these products at this time.<ref>[https://www.homebrewtalk.com/threads/anyone-try-those-cheap-ebay-motorized-grain-mills.688262/ Anyone try those cheap eBay motorized grain mills?] | *'''Suspicious budget mills''' such as the [https://www.vevor.com/products/electric-grain-mill-barley-grinder-malt-crusher-hold-up-to-11lbs-crushing-dy-368 motorized] and [https://www.vevor.com/products/grain-mill-barley-grinder-malt-crusher-3-roller-wheat-home-brew-food-industry 3-roller] mills at Vevor - These cheap mills have a number of {{amazon|B07D1Y51WT|bad reviews}} and generally don't have a strong track record, so we don't recommend these products at this time.<ref>[https://www.homebrewtalk.com/threads/anyone-try-those-cheap-ebay-motorized-grain-mills.688262/ Anyone try those cheap eBay motorized grain mills?] Homebrew Talk website. 2020–2021. Accessed Jan 4 2021.</ref> | ||
*'''Non-roller mills''' such as food processors, rolling pins, or Corona/Victoria style disc mills ({{Amazon|B00JZZKLHI|example}})<ref>[https://www.homebrewtalk.com/threads/my-ugly-junk-corona-mill-station.90849/ My ugly junk- Corona mill station.] | *'''Non-roller mills''' such as food processors, rolling pins, or Corona/Victoria style disc mills ({{Amazon|B00JZZKLHI|example}})<ref>[https://www.homebrewtalk.com/threads/my-ugly-junk-corona-mill-station.90849/ My ugly junk- Corona mill station.] Homebrew Talk website. 2008–2020. Accessed 2020.</ref> - These tools are not designed to create a proper crush, they're not easily adjustable, they tend to create a mess and/or require significant modification just to be useable.<ref name=bsp/> Corona-style mills are generally low-quality products (e.g. they may add metal shavings to the grist). Buy pre-milled grain until you're ready to invest in a roller mill. | ||
== Mounting the mill == | == Mounting the mill == | ||
It is important to set up the mill on a base to keep the frames aligned properly. If the frames aren't straight, the rollers may bind.<ref>[https://www.monsterbrewinghardware.com/store/pc/catalog/MM-2-3-20Instructions.pdf "Monster Mill MM 2/3/PRO Instructions."] Monster Brewing Hardware, 2015.</ref> As you are securing it to the base, make sure all the rollers spin freely. Most mills either come with a base or have one available. These bases are typically designed to let the mill sit on top of a plastic bucket, and this setup is fine in most cases. However if you are adding a dedicated motor, it will be necessary to attach the mill to a larger base or table. | It is important to set up the mill on a base to keep the frames aligned properly. If the frames aren't straight, the rollers may bind.<ref>[https://www.monsterbrewinghardware.com/store/pc/catalog/MM-2-3-20Instructions.pdf "Monster Mill MM 2/3/PRO Instructions."] Monster Brewing Hardware, 2015.</ref> As you are securing it to the base, make sure all the rollers spin freely. Most mills either come with a base or have one available. These bases are typically designed to let the mill sit on top of a plastic bucket, and this setup is fine in most cases. However if you are adding a dedicated motor, it will be necessary to attach the mill to a larger base or table. | ||
Monster Mill accessories like {{Amazon|B0064OMA04|this base}} will also work for the Kegco 3-roller mill. | |||
== Driving the mill == | == Driving the mill == | ||
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=== Electric drill === | === Electric drill === | ||
[[File:Milling-drill.png|thumb|Driving the mill with a cordless drill. Photo by Rob Stein.]] | [[File:Milling-drill.png|thumb|Driving the mill with a cordless drill. Photo by Rob Stein.]] | ||
For most home brewers a drill is the preferred method to drive a mill. It is easier to set up and more economical than using a non-drill motor, and significantly less laborious than hand cranking. Low RPM drills provide the best torque. We don't recommend using an external speed limiter ({{Amazon|B00U3LD1WA|example}}) on a high RPM drill because they significantly reduce the torque.<ref>[https://www.homebrewtalk.com/threads/speed-controller-for-corded-drill-used-for-milling-grain.629645/ Speed controller for corded drill, used for milling grain?] | For most home brewers a drill is the preferred method to drive a mill. It is easier to set up and more economical than using a non-drill motor, and significantly less laborious than hand cranking. Low RPM drills provide the best torque. We don't recommend using an external speed limiter ({{Amazon|B00U3LD1WA|example}}) on a high RPM drill because they significantly reduce the torque.<ref>[https://www.homebrewtalk.com/threads/speed-controller-for-corded-drill-used-for-milling-grain.629645/ Speed controller for corded drill, used for milling grain?] Homebrew Talk website. 2017. Accessed 2020.</ref><ref>[https://www.homebrewersassociation.org/forum/index.php?topic=23703 Monster mill drill question.] American Homebrewers Association website. 2015. Accessed 2020.</ref> Affixing a zip tie, 2" tri-clamp, or U-bolt to the trigger of a variable speed drill can help control and maintain a constant speed. A corded drill is generally more powerful than a cordless one, and will usually last longer. However cordless drills can also work well.<ref>[https://www.beeradvocate.com/community/threads/need-drill-recommendations.581479/ Need drill recommendations.] BeerAdvocate website. 2018. Accessed 2020.</ref><ref>[https://www.homebrewersassociation.org/forum/index.php?topic=9367 Proper drill for milling grain.] American Homebrewers Association website. 2011. Accessed 2020.</ref> The one requirement to using a drill is that the drill chuck fits onto the mill drive shaft (which range from 3/8" to 1/2" [9-12mm]). If you are holding the drill while milling, you must also hold down the base of the mill. Otherwise the torque may cause the mill to flip over, causing damage to equipment and/or personal injury. | ||
{| class="wikitable" | {| class="wikitable" | ||
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==Setting the gap== | ==Setting the gap== | ||
[[File:Angled-feeler-gauge.png|thumb|An angled feeler gauge for measuring the roller gap on a 3-roller mill. Photo by Dr. Adam Bittner]] | [[File:Angled-feeler-gauge.png|thumb|An angled feeler gauge for measuring the roller gap on a 3-roller mill. Photo by Dr. Adam Bittner]] | ||
All of the mills we recommend have an adjustable roller gap. A tighter gap produces smaller grain particles, called a fine crush, and a larger gap creates a coarse crush. '''There is not a one-size-fits-all gap setting.''' The ideal mill gap setting is dependent on your mill, your brewing system, and factors related to the grain (which can vary even from batch to batch and with storage time).<ref name=Kunze/><ref name=Crescenzi>Crescenzi AM. [https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2050-0416.1987.tb04498.x Factors governing the milling of malt.] ''J Inst Brew.'' 1987;93:193–201.</ref><ref name=delucchi>Delucchi V. [https://byo.com/article/the-perfect-crush/ The perfect crush.] Brew Your Own website. 2019. Accessed January 2021.</ref> For each batch the objective is to find an acceptable middle ground between lautering/recirculation effectiveness, efficiency (yield), and quality.<ref name="Briess">Hansen B. [http://www.brewingwithbriess.com/Assets/Presentations/Briess_2007CBC_Practical_Milling.ppt Practical milling for the craft brewer.] Briess Malt & Ingredients Co. 2007. Accessed 2020.</ref><ref name=smart3>Holbrook CJ. Brewhouse operations. In: Smart C, ed. [[Library|''The Craft Brewing Handbook.'']] Woodhead Publishing; 2019.</ref> Some experimentation with different settings is needed to find out what works best for your mill and your brewing system, although there is a wide range that will be adequate.<ref>[http://www.themodernbrewhouse.com/forum/viewtopic.php?f=2&t=1795 Mashing for high gelatinisation temps.] The Modern Brewhouse website. 2020. Accessed 2020.</ref> Also, the grist should be visually monitored every milling to ensure it is being properly crushed. | All of the mills we recommend have an adjustable roller gap. A tighter gap produces smaller grain particles, called a fine crush, and a larger gap creates a coarse crush. '''There is not a one-size-fits-all gap setting.''' The ideal mill gap setting is dependent on your mill, your brewing system, and factors related to the grain (which can vary even from batch to batch and with storage time).<ref name=Kunze/><ref name=Crescenzi>Crescenzi AM. [https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2050-0416.1987.tb04498.x Factors governing the milling of malt.] ''J Inst Brew.'' 1987;93:193–201.</ref><ref name=delucchi>Delucchi V. [https://byo.com/article/the-perfect-crush/ The perfect crush.] Brew Your Own website. 2019. Accessed January 2021.</ref> For each batch, the objective is to find an acceptable middle ground between lautering/recirculation effectiveness, [[efficiency]] (yield), and quality.<ref name="Briess">Hansen B. [http://www.brewingwithbriess.com/Assets/Presentations/Briess_2007CBC_Practical_Milling.ppt Practical milling for the craft brewer.] Briess Malt & Ingredients Co. 2007. Accessed 2020.</ref><ref name=smart3>Holbrook CJ. Brewhouse operations. In: Smart C, ed. [[Library|''The Craft Brewing Handbook.'']] Woodhead Publishing; 2019.</ref> Some experimentation with different settings is needed to find out what works best for your mill and your brewing system, although there is a wide range that will be adequate.<ref>[http://www.themodernbrewhouse.com/forum/viewtopic.php?f=2&t=1795 Mashing for high gelatinisation temps.] The Modern Brewhouse website. 2020. Accessed 2020.</ref> Also, the grist should be visually monitored every milling to ensure it is being properly crushed. | ||
There are two main things to consider when experimenting with the roller gap: | There are two main things to consider when experimenting with the roller gap: | ||
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Process: | Process: | ||
# Insert the gauge into a loose gap and then gently tighten the rollers on it. The blades should go into the gap between the rollers with a minimum amount of force, and should not be crushed in the gap. Adjust the gap on both ends of the roller to be the same.<ref name=monster/><ref>Ream J. [http://www.homebrewengineer.com/adjust-mill-gap-barley-crusher/ How to: adjust the mill gap of a barley crusher.] Homebrew Engineer blog. 2015. Accessed 2020.</ref> | # Insert the gauge into a loose gap and then gently tighten the rollers on it. The blades should go into the gap between the rollers with a minimum amount of force, and should not be crushed in the gap. Adjust the gap on both ends of the roller to be the same.<ref name=monster/><ref>Ream J. [http://www.homebrewengineer.com/adjust-mill-gap-barley-crusher/ How to: adjust the mill gap of a barley crusher.] Homebrew Engineer blog. 2015. Accessed 2020.</ref> | ||
# On mills with adjustment knobs, mark on the frame what the gap is at the a variety of knob positions. This | # On mills with adjustment knobs, mark on the frame what the gap is at the a variety of knob positions. This allows you to repeat different gap settings without needing the feeler gauge again. We suggest marking increments every 0.005" (0.1mm) over a range of 0.020" to 0.055" (0.5–1.4mm). | ||
== Milling considerations == | == Milling considerations == | ||
Several things should be considered when deciding on mill gap and other parameters that will affect grist performance during mashing. | Several things should be considered when deciding on mill gap and other parameters that will affect grist performance during [[mashing]]. | ||
=== Husk integrity === | === Husk integrity === | ||
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However, fine milling does not ''necessarily'' cause extraction of harsh flavors, and it can be acceptable depending on the [[lautering]] method.<ref name=bsp>Briggs DE, Boulton CA, Brookes PA, Stevens R. [[Library|''Brewing Science and Practice.'']] Woodhead Publishing Limited and CRC Press LLC; 2004.</ref><ref name=derouck>De Rouck G, Jaskula-Goiris B, De Causmaecker B, et al. [https://www.brewingscience.de/index.php?tpl=table_of_contents&year=2013&edition=0001%252F0002&article=82374 The impact of wort production on the flavour quality and stability of pale lager beer.] ''BrewingScience.'' 2013;66(1/2):1–11.</ref> [[brewing pH|Mash pH]] strongly influences the extraction of negative compounds, which can be particularly troublesome when [[Sparging|fly sparging]]. Therefore the issue of undesirable flavor extraction from pulverized husks may be less worrisome for home brewers who properly control mash and sparge pH, although husk pulverization may still lead to other issues such as haze and excessive trub depending on other factors.<ref>De Rouck G, Jaskula B, De Causmaecker B, et al. [https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-2013-0113-01 The influence of very thick and fast mashing conditions on wort composition.] ''J Am Soc Brew Chem.'' 2013;71(1):1–14.</ref> | However, fine milling does not ''necessarily'' cause extraction of harsh flavors, and it can be acceptable depending on the [[lautering]] method.<ref name=bsp>Briggs DE, Boulton CA, Brookes PA, Stevens R. [[Library|''Brewing Science and Practice.'']] Woodhead Publishing Limited and CRC Press LLC; 2004.</ref><ref name=derouck>De Rouck G, Jaskula-Goiris B, De Causmaecker B, et al. [https://www.brewingscience.de/index.php?tpl=table_of_contents&year=2013&edition=0001%252F0002&article=82374 The impact of wort production on the flavour quality and stability of pale lager beer.] ''BrewingScience.'' 2013;66(1/2):1–11.</ref> [[brewing pH|Mash pH]] strongly influences the extraction of negative compounds, which can be particularly troublesome when [[Sparging|fly sparging]]. Therefore the issue of undesirable flavor extraction from pulverized husks may be less worrisome for home brewers who properly control mash and sparge pH, although husk pulverization may still lead to other issues such as haze and excessive trub depending on other factors.<ref>De Rouck G, Jaskula B, De Causmaecker B, et al. [https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-2013-0113-01 The influence of very thick and fast mashing conditions on wort composition.] ''J Am Soc Brew Chem.'' 2013;71(1):1–14.</ref> | ||
Husk integrity can be improved by conditioning the grain, | Husk integrity can be improved by conditioning the grain, using an appropriately large mill gap, and using a 3-roller mill or a mill with fluted rollers. | ||
=== Milling speed === | === Milling speed === | ||
In general, a milling speed between 50–300 RPM is considered appropriate for | In general, a milling speed between 50–300 RPM is considered appropriate for small scale milling.<ref name="lob271"/><ref name="LOB-1069"/><ref name="monster"/><ref name="bison"/> Be aware that it usually takes a little more torque to get the mill going. If your drive method is struggling, use the method to reduce torque described above. | ||
Some home brewers have found that milling at a lower speed reduces damage to husks.<ref name=lob993/><ref name=lob271>[http://www.themodernbrewhouse.com/forum/viewtopic.php?f=2&t=271 Conditioned grain mill gap.] The Modern Brewhouse website. 2017–2018. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/so-what%E2%80%99s-the-right-harbor-freight-drill-for-a-mill-20-off-coupon-out-now.673941/ So what's the right Harbor Freight drill for a mill? 20% off coupon out now.] | Some home brewers have found that milling at a lower speed reduces damage to husks.<ref name=lob993/><ref name=lob271>[http://www.themodernbrewhouse.com/forum/viewtopic.php?f=2&t=271 Conditioned grain mill gap.] The Modern Brewhouse website. 2017–2018. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/so-what%E2%80%99s-the-right-harbor-freight-drill-for-a-mill-20-off-coupon-out-now.673941/ So what's the right Harbor Freight drill for a mill? 20% off coupon out now.] Homebrew Talk website. 2020. Accessed 2020.</ref><ref>[https://www.homebrewtalk.com/threads/best-place-to-get-a-grain-mill.700592/post-9272893 Best place to get a grain mill.] Homebrew Talk website. 2022. Accessed May 27, 2022.</ref> Other brewers have not noticed a significant effect of milling speed on the grist (appearance or granulometry),<ref>[http://www.themodernbrewhouse.com/forum/viewtopic.php?f=11&t=1929 Milling test results.] The Modern Brewhouse website. 2020. Accessed July 2020.</ref><ref name=bittner/> which is in agreement with professional literature.<ref name=Warpala/><ref name=Mousia/> | ||
=== Oxidation === | === Oxidation === | ||
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=== Specialty grains === | === Specialty grains === | ||
Lighter color kilned or dry roasted specialty malts will crush like base malts, while caramel/crystal and extremely dark roasted products are more brittle and tend to shatter rather than crush. Malts that shatter tend to create more flour which can | Lighter color kilned or dry roasted specialty malts will crush like base malts, while caramel/crystal and extremely dark roasted products are more brittle and tend to shatter rather than crush. Malts that shatter tend to create more flour which can contribute to difficulties during [[lautering]]. The fine particles can fill in the spaces in the otherwise permeable bed causing a slowed or stuck lauter. These brittle specialty malts can typically be milled with a wider mill gap resulting in a larger particle size that will still allow for complete flavor and aroma extraction which is the primary function of these malts. Finding the balance of desired particle size starts with adjusting the mill gaps.<ref>Geurts J. [http://blog.brewingwithbriess.com/9-5-grind/ 9-5 grind.] Briess blog. 2018. Accessed 2020.</ref> | ||
'''Wheat, rye, and oats'''<br/> | '''Wheat, rye, and oats'''<br/> | ||
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=== Dust === | === Dust === | ||
To avoid excessive dust contaminating your gear and wort, it's considered prudent to mill away from your cold side gear and away from where you'll be chilling and fermenting your wort, particularly if you do not condition the grain. Conditioning can help lower the amount of dust generated while milling. However, dust can still be created when measuring the grain. Wearing a mask can be beneficial for your health since breathing in grain dust is not so great.<ref name=mostra/> Thanks to COVID-19 you do have a mask, right? | To avoid excessive dust contaminating your gear and wort, it's considered prudent to mill away from your cold-side gear and away from where you'll be chilling and fermenting your wort, particularly if you do not condition the grain. Conditioning can help lower the amount of dust generated while milling. However, dust can still be created when measuring the grain. Wearing a mask can be beneficial for your health since breathing in grain dust is not so great.<ref name=mostra/> Thanks to COVID-19 you do have a mask, right? | ||
==Conditioning the grain== | ==Conditioning the grain== | ||