Milk contains amylase....

[TimT]

I've been planning another milk brew so I've been reading around the subject lately. You know the drill about using milk: what you're interested in is lactose, an unfermentable sugar. You can buy the lactose on its own, but you'll also get a lot of it in whey, which separates out from the rest of the milk after curdling to make cheese - and it would definitely (maybe, probably, according to a few blogs I read that I can't find now) have been used as a traditional brewing ingredient. I've used it! it's good!

Anyway, I was interested to find recently that milk contains amylase as well, so there might be added benefits in using it in the brewing process. Here's a paper on the subject, containing lots of fancy scientific jargonificating and figures that I'm not very good at understanding. Apparently the amylase levels in cheese are pretty much the same as those in milk, which (maybe, probably, who knows) suggests it disperses evenly between the curds and the whey.

The other thing is, of course, pasteurisation of milk might ruin some of the amylase.... which is why I got to that paper in the first place. It's true, it does, but by the sounds of it modern pasteurisation is very short (under a minute), whereas the amylase in milk degrades at high temperatures over a longer period of time (half an hour). So, raw milk is best, but pasteurised milk will do.

If anybody who actually understands these papers wants to read it and tell me I'm a dickhead and I'm all wrong, go ahead!

Of course, one take away message from this paper might be you can not only use milk in brewing, but you can use cheese in brewing too. A cheese beer? Yeah, nah, I'm not going to go there. Yet. :drinks:

 

[Mardoo]

You DO get very interesting flavor development from white cheese molds...

 

[philmud]

So how are you planning on using the milk? In place of a mash? To supplement a mash? What kind of beer? Is it worth steeping some cracked grains in milk or a milk/water solution and doing a before:after SG comparison?

 

[peas_and_corn]

Using milk in brewing for its amylase is like buying an apple to use as a paperweight. It might do something to help, but what's the point? Malted barley has more than enough enzymes to convert the starch into sugar.

 

[TimT]

The other thing I should have added is the temperature at which the enzyme works according to those experiments - most starch to sugar conversion happens at around 45 degrees celsius. That's at the bottom end of the 'starch rest' other brewers talk about. (I've never really done one of those). Maybe it's not the familiar alpha amylase or beta amylase we use in brewing, but one of those ones that works at the lower temperature range. Or maybe they just work differently in milk?

Prince Imperial - they do have some figures at the linked paper but I don't know what they would mean for the use of milk amylase in brewing and/or how they would compare to the use of malted barley amylase. I was thinking of chucking whey into the mash, doing it for half hour at around 45 degrees celsius and then upping it to 65 or so for another half hour. Maybe a brown or black brew, since they seem to hold the sweet lactose flavours and creaminess better. Partly the thing is I've run out of my usual base malt; I have Munich which I think could do as a base (not too crystally), but I've read that it doesn't have enough conversion power for adjunct grains. So I thought maybe some extra amylase could help matters along.

Also, the active lacto-bacilli in whey might bring a slight sourness to the mash, akin to that sourness that acidulated malts might bring. I'm not averse to this... so long as it doesn't go overboard.

Peas and Corn - I take your point, but partly my desire to do this arises out of my interest in historical brewing. I have an idea that in earlier times, when brewing science was not so exact, the addition of adjuncts that contained amylase would have been quite useful (as well as adding interesting flavours). And, as I find myself in a situation (see above) where I have a potential malt that may not have quite so much enzymatic conversion power as desired, well....

 

[TimT]

i should also mention this here book I have - the 18th century 'Booke of Cookery' by Martha Washington (essentially her home cookery book). In it she has several recipes for 'Possets' which involve things like boiling barley in cream. This suggests to me a crude early form of custard, where the amylase in the milk enables some form of malting process to get underway. Interesting stuff....

 

[MHB]

Tim you are a dickhead!
The first paragraph of the article says there is no Amylase in Cows milk, the test was done on Human milk.
Some of the other references found some Amylase in cows milk - from that you have composed an argument that Cows milk contains Amylase and might be good in brewing.
From paragraph 3/.. enough amylase to convert 15-20mg/100ml, so taking the 20mg as a possible to get enough amylase to make 1L of 1.040 wort (10oP) or 10%W/W sugars, so to make 100g of extract you would need the Amylase from 500L of milk
20mg = .02g, 100/.02=5,000 (as it was / 100ml) 5,000/10 = 500.

So unless your missus is much more cooperative than the average, you are going to be very hard pressed to conduct anything like a meaningful experiment.
Tim you come up with some interesting ideas, but you also engage in some remarkable flights of fancy - this I suspect is one of them. There is a real element of science in brewing, you really should learn some of it.
Mark

 

[TimT]

No, the experiment was on cow's milk, at the head of this page they specify that the milk was supplied by the Sheffield Farm Company. The wording up to that point is a little ambiguous and perhaps it was misleading of them to mention human milk in the opening paragraph. But it's an experiment on the amylase in cow's milk.

 

[MHB]

Moving along to page 124 where the results are


10cc (mL) can convert .002g, so 1L of milk 100*10ml could convert 0.2g of starch. to convert 100g you need 100/.2=500L of milk
Tim seriously it would take all the amylase in 500L of milk to make 100g of extract (1L @ 1.040)

There is more Amylase in in a couple of good spits - not suggesting you gob in your beer, or in 125g of malt, which is where we have been getting our amylase form for the last 10,000 years or so.
If you really want to look at traditional brewing - look at malt that's where it all started.
Mark

 

[TimT]

Yeah, might leave the chicha experiment for another time.

 

[Feldon]

I thought that the key feature of enzymes (eg. amylase) was that they cause a reaction in other compounds but remain unchanged themselves. Eg. enzyme molecules bump into big starch molecules and cause them to break apart into smaller sugar molecules. The enzymes are unchanged by this reaction and can do the same again when they meet up with more starch molecules. So its not a matter of how much enzyme you have but how long you put it to work?

 

[TimT]

Yep, and that's one of the things they look at in the experiment - the longer the enzyme is active, the more starch is converted.

One other thing that comes to mind is, does the enzymatic conversion thing operate on a simple formula - so, if you have x amount of enzymes doing their thang in a brew, and then you double those enzymes to 2x, does the starch conversion double as well (all other things being simple)? Or is it more complicated than that? (Though, as Mark has helpfully pointed out here, it does look like what the enzymes in milk will bring to the party will be pretty minimal anyway.)

 

[klangers]

I thought that the key feature of enzymes (eg. amylase) was that they cause a reaction in other compounds but remain unchanged themselves. Eg. enzyme molecules bump into big starch molecules and cause them to break apart into smaller sugar molecules. The enzymes are unchanged by this reaction and can do the same again when they meet up with more starch molecules. So its not a matter of how much enzyme you have but how long you put it to work?

All catalysts require a certain excess in order to drive the equilibrium to the product side. If you don't have enough enzymes, they will work until a certain concentration and then stop.

Yep, and that's one of the things they look at in the experiment - the longer the enzyme is active, the more starch is converted.

One other thing that comes to mind is, does the enzymatic conversion thing operate on a simple formula - so, if you have x amount of enzymes doing their thang in a brew, and then you double those enzymes to 2x, does the starch conversion double as well (all other things being simple)? Or is it more complicated than that? (Though, as Mark has helpfully pointed out here, it does look like what the enzymes in milk will bring to the party will be pretty minimal anyway.)

Since it involves organic chemistry, I can almost guarantee you it's not a linear relationship. It's not my area of science but you've got me thinking and I might brush up on my brewing science.

 

[TimT]

Ah, interesting, thanks Klangers.

Some recipes call for you to mash the brew for hours - indeed, some traditional brewing techniques have mashes lasting days - which indicates that, provided you keep the brew in the right temperature range, you'll get more and more enzymatic action as time goes on.

I've assumed in my brew that what Mark says is correct, that any amylase action you're going to get from milk/whey will be minimal and that it's only going to provide a small amount of starch conversion as opposed to that that you're going to get from the amylase in the malted barley. Anyway, I'm cooling my brew down at the moment. So I'll be interested to see how it all turns out!

 

[klangers]

Essentially, the enzymes act as a catalyst by reducing the activation energy of the reaction. This then speeds up the reaction in the order of a million times faster. However, as the concentration of product:reactant changes, so does the speed of the reaction. This is compensated for by having a large(r) concentration of catalyst which increases the probability of a starch molecule encountering an enzyme molecule.

Therefore whilst it is possible to get conversion from a small amount of enzyme, you could be waiting for so long that the whole mash goes off.

Otherways of compensating for a small amount of enzyme is to increase the amount of agitation by mixing the mash around to also increase the probability of the molecules meeting.

 

[MHB]

Ah, interesting, thanks Klangers.

Some recipes call for you to mash the brew for hours - indeed, some traditional brewing techniques have mashes lasting days - which indicates that, provided you keep the brew in the right temperature range, you'll get more and more enzymatic action as time goes on.
Snip

[SIZE=medium]Really, the longest I have ever read about was mashing in cold the night before, which does improve the yield minimally, the exception being in the manufacture of acid malt. We aren't bio-acidifying here we are talking about amylase and mashing.[/SIZE]

[SIZE=medium]To say enzymes are like catalysts is an analogy and like most analogies it cant be trusted as a complete explanation. Catalysts are the domain of inorganic chemistry, things like Platinum and Nickel dust and a whole bunch of salts and oxides of metals (among others). Catalysts are generally unchanged by the reaction and unless you chose the wrong one are still there unchanged at the end of the reaction. [/SIZE]

[SIZE=medium]Enzymes on the other hand are protein structures, they do something similar to what catalysts do but its by a very different method. They are (excuse analogy) very much like a living thing, they have an energy budget (they have to get something out of the process).[/SIZE]

[SIZE=medium]They have a finite life, they will only do a certain amount of work then they denature (die). They will work slowly for a long time or fast for a short time but in the end under the right conditions they will do the same amount of work fast or slow.[/SIZE]

[SIZE=medium]The caveat being that all enzymes are different, they have ideal pH temperature and concentration requirements, some are tough and some very fragile. The Alpha and Beta Amylase contained in malt being a case in point. Beta Amylase is fragile, it won’t work for very long, it is very intolerant of temperatures above 65oC and is fairly finicky about pH. Alpha on the other hand is quite robust, works over a much larger temperature range, can cope with a much wider pH range and with higher Calcium content in the mash it can work a lot longer and harder than most people think.[/SIZE]
[SIZE=medium]Enzymes from the material being mashed (malt) are called endogenous, if you are adding something from another source they are referred to as exogenous enzymes, you can buy both Alpha and Beta Amylase (mostly Alpha) most of these are from bacteria, mostly GM bacteria, some of the exogenous Alpha can work up to 95oC. God only knows what the ideal conditions for milk amylase would be, given you could collect enough of it to be of any use.[/SIZE]

[SIZE=medium]If you can point to any mashing process that takes days I would like to look at it, personally I think you "misinterpreted" what you read.[/SIZE]
[SIZE=medium]There is no point in mashing for longer than the enzyme will keep working. At its activity peak for Beta Amylase 63-65oC that’s around 15-30 minutes, for Alpha 45-60 minutes in most mash conditions (may be a bit longer at lower than the peak of 72oC).[/SIZE]
[SIZE=medium]Any way you look at it mashing for anything over two hours is probably a waste of time.[/SIZE]
[SIZE=medium]Mark[/SIZE]

 

[TimT]

MHB, I'm pretty sure I've read about it in several places - mind, I am referring to traditional brewing where techniques and knowledge were more imperfect than what they are today. But here's a translated quote from an observer of the Chewsurian method of making ale (some kind of Germanic people, I suppose). I've bolded the relevant bit.

From the brewer of Saint Michael there escaped a continuous cloud of smoke. Malting was going on there, and the acrid smoke, occasioned by the damp brushwood which had to serve as fuel, together with the escaping steam wrapped the brewhouse completely in a dusky mantle. The brew-house, too, was built in the rudest way, low and insufficiently lighted. There, by a mighty chain, hung the huge copper brew-kettle. Its form is peculiar, and everywhere the same. In its form it most closely resembles a giant top, being from 1 1/2 to 2 arsheen high (3 1/2 to 4 1/2 feet) and at its greatest width about 1/14/ arsheen (3 feet) wide. It begins to belly out at a point above the middle. Artisans of Telaw fashion caldrons like these, their value being somewhere between 100 and 200 roubles. Laterally, this cauldron is held up by carelessly joined stone rubble, while sooty flame licked at it in front and behind. The mash was bubbling in it at a uniform rate, and was stirred now and then. Water was conveyed from the nearby brook through a small pipe that was laid against the outer edge of the cauldron. The crushed barley that is used for the mash is coarse, and is boiled steadily for several days at an even temperature. Then the brew is run into woolen bags, and the latter are fastened above the rim of a vat, using wooden hoops for the fastening, so that the liquid slowly runs into the vat below. The fresh brew thus made, is turbid, rather insipid, and sweetish in flavour. It is poured into tubs 3 or 4 feet high, and 2 to 2 1/2 feet wide, made of one piece (from sections of tree trunks hollowed out), basswood being mostly used for this purpose. Then the required amount of Kakhetian wild hops is added, and the liquor, well covered up, is allowed to stand for 5 or 6 days.

I found this passage in Randy Mosher's Radical Brewing. A longer quote is here. Given what you say, perhaps the method of mashing here involved continuously adding more water and more barley to the mash.

 

[manticle]

Sounds like an extended decoction.
My understanding is that one of the original purposes of decoction was to degrade starches in malt that was far less modified than it is currently.

 

[MHB]

there are several problems there
you cant mash at boiling temperatures, so I strongly suspect the "observer" wasn't an expert on brewing and had no idea what was really going on.
the one thing I can agree with you on is that, the further back in time you go the less we knew about brewing. where we come unstuck is I believe we should use knowledge to make better beer, from what I have read of your posts you appear to think the exact opposite, should we stop making good beer and try to recreate some historic and probably unpleasant brew?

 

[crozdog]

"The mash was bubbling in it at a uniform rate" sounds like they were doing a cereal cook rather than "mashing". The poor quality malt available made terchniques like cereal cooking & decoction necessary.

My suspicion is there was more to the process that the 'observer' didn't see / wasn't told about & therefore didn't describe.

Send Randy an email - he's a great guy who will respond with his views on the 'Chewsurian method"