mash tanks and later tuns - why are both required?

[perfection]

I have always wondered why both mash tuns and lauter tuns are required in a beer production operation. Why can't mashing be done in a lauter tun and then lautered and sparged in single batch operation. What distinct advantage is achieved by doing such operation in mash tank followed by lauter tun or may I ask what distinct disadvantage is there in having MLTs more universally in breweries

[UnFermentable]

Mashing and Lautering are both required in brewing from raw ingredients. The former for enzymatic activity and the latter for separation of solids. Obviously there is much detail in these processes.

There is no requirement that this be done in separate vessels. There are many different designs of Brewhouse that can accommodate these processes.

Generally Brewhouse design is factored by desired output volume, price, sizing limitations, efficiency, brewing techniques, and much more.

Combined Mash/Lauter tuns are very common in simple “pub” type systems, while often production breweries use different configurations for more throughput. There are advantages to separating the mashing and lautering processes when using cereal grains or under modified malts among other things. It is becoming more common to see a combined mash mixer/kettle and a separate lauter in some “pub” type systems to accommodate for the advanced brewing techniques.

[perfection]

Is it not that extraction of wort would be more thorough in a dedicated lauter tun (used after mashing) or are there any other advantages too?

Does this effect the cloudiness of the (sweet) wort in any way or is that due to altogether other factors?

[Natrat]

In my experience, there is no qualitative difference between using a mash/lauter process vs a seperate mash kettle and lauter tun.
From an upgrade perspective, many people with an insulated (rather than jacketed) lauter tun may want to buy a jacketed mash tun in order to graduate to stepped temperatures. But the main reason to have separated vessels is because brewing is a batch process. More vessels mean a shorter multi-batch workday. With separate mash, lauter, kettle, and whirlpool, it is possible to have 4 overlapping batches in throughput all at once.
Limited space operations can use combi-vessels, but it makes high-output harder. I used to have a single vessel that had HLT, Mash, Lauter stacked on top of one another!

[gitchegumee]

I'm old school. Equipment discussions for mashing are almost the first thing you'd encounter in a brewing book. There are dozens of reasons to choose a dedicated mash mixer & dedicated lauter tun. And dozens of reasons to combine mash mixer & kettle. The only reasons I can think to combine mash & lauter is for cheaper equipment and less flexibility in mashing techniques. But for such basic information, turn to any of the fine textbooks available to brewers. I think that everyone professing to be a brewer should have read at least a few of the classics: Brewing Science and Practice by Briggs et al; Brewing by Lewis; or the seminal Textbook of Brewing by Jean DeClerck are good places to start. I'm old school and believe that having reference books trumps an internet connection when it comes to learning these basics. And being old-school I'm also endeared to the classic 2-volume textbook sets that provide a solid foundation for brewing science. Of the many, many, many brewing books published in the last 20 years targeting "craft" brewers, I find few more useful for creative inspiration as Randy Mosher's excellent Radical Brewing. There are other threads on which books folks like, my point is that this is something perhaps better left for print rather than discussion. But I'm old school.

[beerme]

There are 2 major types of mashing/ wort separation systems: coming from British, and German traditions.
In Britain they had more well modified malt than in eutope, meaning that they could crush their grain more coarsely and still get good extraction of the sugars. They would often mix the grist and water in a steeles masher, with as little as 2.5:1- 2:1 liquor to grist ratio. (2L of water per kg of grain). In mashing there would be entrained air bound to the grist which created a "floating mash" effect.

The British style mash tun often has a mash depth of 4-5' or deeper, and usually does not have rakes or grain out ploughs. The wort runoff and sparge water are coordinated so the grain "floats" so it does not compact allowing the water to flow through the grain bed. Extract from within the grist pieces diffuses into the wort stream flowing by.

This system is suited to a single step mash where it is mashed in at one temperature, (~64-68C) and run off after starch conversion has taken place. The well modified malt has plenty of enzymes to break down the starch under these conditions.


In the "German" system, they often did not have as well modified malt, meaning the starch was less available, and less enzymatic (diastatic) power (Dp). They made a looser mash of 3-5:1 to allow pumping. They would go through a step mash, originally heating by "decoction" where they would take some out, heat it in a separate kettle and return to mash to bring temperature up. Now often the "mash mixer" has steam jackets and an agitator, to allow this to happen in one tank. The brewer is able to select the temperature "rests" he wants to reach, to favour specific mash enzymes in order to get the resulting wort characteristics he desires.

The mash is pumped to the Lauter tun, which often has a much shallower grain bed of ~2' or less. it usually has rakes to cut and lift the grain bed. The wort is drawn off, often is stages where they draw off the liquid and then "refloat" the mash with sparge water while running the rakes to lift the bed and make it more permeable. because of the smaller particles, it would otherwise tend to make a stuck mash, not allowing the water to permeate through.

The German mash mixer/ lauter system allows the brewer more control to manipulate the mash conditions to get the enzymes to create the extract they want, and control proteins, fermentability and more. it is more sophisticated and complicated.

The British system is simpler and more basic. It is sufficient for most smaller microbreweries and costs less to make. Some Mash tuns were built with steam jackets but they do not work well as mixers, so it is difficult to get the temperature even.

[UnFermentable]

No love for the mash filter!?! They aren’t as “new” as most people think!

[gitchegumee]

One of my favorite breweries in the world, Rodenbach, switched to filters when they sold. Gotta say I'm not impressed with how they executed mash filters--or the whole buy-out in general--can't lay that solely on mash filters. I like the simplicity and gentle handling of a mixer/lauter as opposed to hammer mill and filter. Again, old-school. Unless I find a trend of better beers with filters; then what isn't broken doesn't need fixing.

[dick murton]

Mash filters are a great alternative to lauter tuns, and can obtain higher extract values than even a modern highly automated lauter tun system. BUT, the cost of the automation required to operate these beasts, additional maintenance costs (mainly sheet replacement) means that the additional extract obtained only really pays for itself if producing large volumes, and particularly when running a 24/7 operation. I know there are smaller (25 hl upwards) setups, but I would like to see the cost justification. Because some are sold, there must be operating conditions when they are advantageous. Another major advantage for MFs is the ability to cope with Cassava or sorghum brewing far more easily than LTs, let alone MTs, so they are increasing used in Africa where these materials are used. A disadvantage of an MF is the ability to vary the grist weight very much as you have to fill with a standard malt and adjunct load. But bear in mind that adjuncts have equivalent mashed volumes, so If I remember correctly (I have some figures somewhere) cassava only occupies half the residual volume of an equivalent mass of barley malt.

Sooo, if you are making ales, using well modified malt, a mash tun will suffice, albeit you will get lower extract figures than the other two systems. They have the advantage of a wide working range, for instance at one brewery, the MTs I worked with could cope with 125% down to 25% of nominal malt grist load. Using suitable malts, you can produce good lagers as well. They are easiest to run as manual or semi automatic, or less commonly as fully automated systems.

A mash mixer / lauter tun system will cope with about 110 to 75% nominal load - or perhaps that is because these were 1980 - 90s technology - newer ones may differ in their flexibility. They will cope reasonably well with non malt adjuncts, but not high levels of adjuncts such as cassava or sorghum. For best results, they need to be automated

A mash mixer / MF system will, if I remember correctly cope with about 105% to 90% of nominal grist weight and can cope with ales and lagers and all sorts of non malt dry adjuncts. Automation is the only option available.

[dick murton]

Forgot to add to one of the earlier responses.

If using a traditional mash tun, the coarse mash traps air and helps the bed float, both the large particle size and the floating due to to trapped air allowing th bed to retain the porosity - so they don't need rakes. And nowadays anything over about 20 hl wort volume size will be fitted with discharge arms. But traditionally, no they were not. Once the engineers could make reliable seals, then discharge rakes started to be fitted.

With a mash mixer / mash conversion vessel and lauter / mash filter setup, the need to use pale colours, poorly modified malts to produce the favoured pale beers meant that you had to mix the mash to get consistent temperatures. This knocked the air out of the mash anyway, so by grinding finer, it meant that not only did you entrain less air during mashing in, so potentially improving flavour and haze in the final product, it mean that the malt particles, being smaller could be saturated with mash water quicker. This was particularly critical with poorly modified malts (for pale colours) as water does not penetrate the far harder grain particles as quickly as highly modified malts. Having knocked all the air out, the mash no longer floats and is far less porous, so rakes were used to help break up the grain bed and maintain porosity. Mash filters get over this problem by having such thin beds that impermeable beds are rarely a problem.

[beerme]

I forgot to mention mash filters and Strain masters while we are at it. I did not want to confuse the issue too much.

IDD in California make a small scale mash filter brewhouse, i believe now as small as 5 bbl. My understanding is that if you want to make a smaller batch you can put in a blocking plate that allows you to only fill number of plates needed.

[dick murton]

Ah. The strainmaster. I worked at a couple of breweries that used them, installed in the 70's. One brewery closed, the other replaced with lauter tuns in the 90's as the SMs didn't really work that well. As I understand it, the only brewery still using one, anywhere in the world, is Camerons, Hartlepool, in the UK. They have probably now got a preservation order on the thing, a bit like an ancient monument!! The idea seemed good, but in practice, the sparging in particular never worked as well as with a lauter tun (or even a mash tun, amazingly) let alone a mash filter, so was very uneven, and didn't produce the extract promised.