What is the point of a Hochkurz mash?

[yankinoz]

I've done them and liked the results on lagers and on ales, but none was in a side-by-side comparison with an immersion mash.

Rationales generally run to achieving a desired balance between products of the action of alpha- and beta-amylase enzymes. But that's what infusion mashes at, say, 65 to 68 are supposed to do. Even the usually very thorough braukaiser, in a Brewer;s Friend post, goes no further, except to say most German breweries use Hochkurz.

Braukaiser writes, "A low temperature rest favors the beta amylase and sets the fermenatbility of the wort. A high temperature rest favors the alpha amylase and completes the starch conversion."

That assumes that there is any starch left to convert at the high end. Braukaiser assumes a rest of 30 minutes at 63 (a graph differs). Conversion follows an asymptotic curve, and the amount of starch left for conversion to dextrins is likely to be small. Fine for pilsners, but why don't they just do an infusin at a temp where beta outruns alpha, maybe somewhere around 65?

Does the Hochkurz mash allow better control and consistency of the final product?

 

[MHB]

I'm unfamiliar with the term "Immersion Mash", do you mean Isothermal (at one temperature)?
Mark

 

[yankinoz]

I'm unfamiliar with the term "Immersion Mash", do you mean Isothermal (at one temperature)?
Mark

Sorry, Mark, I typed wrong thrice (brain fade), meant infusion mash, which does not have to be isothermal, but as you'd .know is usually taken to mean a single rest.

 

[MHB]

Having a Braumeister I tend to think more in terms of "Programmed Infusion" or 'Step Mashing" if you prefer.
These days I generally mash in at ambient (~20oC) check all the pH and water chemistry and work up from there, depending on the malt and style of beer being made.
What I find most interesting the mashing time, it's a fair bit longer than most home brewers think normal. Mind you most brewing texts still talk about 1&1/2-2 hour boils, 90 minute sparges are considered to be high speed...
There are lots of factors that combine to make a good wort with all the properties a brewer is looking for. Starting with malt choices, milling and on to the end.
If you want to do really successful isothermal mashes, I would go with a high quality Ale malt (probably UK), if you really care do an Iodine test to make sure all the starch has been degraded before you run off to the kettle.
Hochkurz mashing would best suit someone doing either Decoctions or Hot Water Infusions (Hot=Boiling in most cases). It is certainly a way to get the most out of brew in a bag.
I really don’t think I can answer your question there are just way too many variables and choices, if it works for you use it, but for mine it’s far from the only to get where you are aiming.
Mark

 

[yankinoz]

MHB,

Braukaiser maintains the German breweries like Hochkurz mashes as a way to get away from rests below 60 and from decoction: "The Hochkurz mash has become the standard mashing schedule for beers brewed in Germany. Especially large breweries like it because it doesn’t require decoction and can be done in less than 2 hours which fits well with their desire to be able to mash a new batch every 2 hours. " Infusion Mashing - German brewing and more
He then mentions both direct heating and hot water additions as possibilities for home brewers, but never really addresses the question, why? It is convenient. In BIAB I have aimed for 62, wait 30 minutes, taken 20-25 minutes of direct heating to raise the mash to 71, then leave it there for 30-40 minutes. Never failed an iodine test. Then mash out.

Presumably the German breweries see some advantage to Hochkurz over single infusion. Keep in mind they're not doing protein or acid rests either way. Maybe I'll try a German brew board, struggle wading through and report back.

I've never tried it on a full-bodied beer, but supposedly some dunkels are made with Hochkurz mashes. If I went that way, I'd probably shorten the time at 62, to carry more starch forward to the higher temps.

If you're relying on direct heat in your Braumeister, how fast does your machine raise temps?

My impression from recipes is that the great majority of home brewers, along with many commercial ale brewers stick with single infusion (isothermal) mashes.

 

[MHB]

It’s a pretty good rule of thumb that a programmed infusion will ramp at or about 1oC/minute. That appears to be the upper limit that you can get heat into the mash without the heating surfaces being so hot that they either scorch the wort or denature the enzymes near the surfaces. Appears to apply to well designed electric elements and steam heated surfaces. Braumeisters obey this rule pretty well.
Clearly direct heat and BIAB has some issues, adding hot (boiling) water is a lot easier and probably faster, of course then you are venturing into 2 vestal systems which BIAB was sort of invented to avoid.
I suspect there is a lot of truth in your impression about home brewers, and small commercial brewers. When it comes to big producers, intensive programmed infusions (steam jackets and rakes) are probably more the norm, but then over a certain size efficiency appears to become the main criteria.
With well made Ale malt Isothermal or better yet an infusion to mashout is very effective and far less expensive to build and operate.
Really not a case of there being a "Right" answer, all I can suggest is try several options and see what works best for you. As a home brewer, I'm happy with 80+% efficiency into the fermenter, which would get you fired - fast in a mega brewery. Me happy to spend an extra couple of dollars on malt and go for the flavours I like.
Mark