[rbowers]

I recently looked over Stone Brewing's book that contains a fair amount of their recipes and I noticed some of these recipes call for significantly shortened mash times compared to the standard 60-90 min I'm used to.  Some are as short as 10-20 min at 157F followed by a mash out step.  What are the effects of this?  Will this add substantially to the body of a beer?
I have often felt my beers are sometimes a bit thin despite higher mash temps.  Is this something worth considering or am I merely going to sacrifice overall yield?  Any thoughts?

[tygo]

With that short a mash time I'd be worried about not achieving complete conversion.  Stone may be able to pull it off because they have their system so dialed in and understand exactly how it works.  At a homebrew level I wouldn't be too confident in a 20 minute mash getting the job done.

You probably can go shorter than 60 minutes, like down to 40, and still get complete conversion.

[hopfenundmalz]

Are they using a base malt with high Diastatic Power?

When they mash in, how long does that take. 20 minutes? More?

How long does it take them to mash out?  I think they have a 200 bbl brewhouse, but it has been a few years since I was on that tour.  This could take a while to raise the temp.

In short, if you use a hot malt (high DP), and know you are getting conversion as you mash in and mash out, the time you spend at the rest can be small.  I mash in fairly quickly, and it does not take long to raise my 10 gallon batches to mash temps.

[sailortodd]

It seems like 10 minutes is very short. At that point, I'd want to conduct a conversion test rather than just trusting that it's done. I have heard about mashes that were conducted at 156-158 range achieving full conversion in 20 minutes, though.

[bluesman]

A short mash time is okay if you can verify that you've achieved complete conversion. My concern is having confidence in knowing that complete conversion has been met in 10 minutes. A refractometer reading will confirm. I have my doubts. Be careful, take a few readings to confirm complete conversion has occurred before you lauter. Waiting another 30min is a very small price to pay in the grand scheme of things.

[veldy]

The tried and true iodine test is probably sufficie even for professional brewing. 

I believe most mash is completely converted in about 15 to 20 minutes, even at a homebrew level, and it will certainly be quicker at a higher temperature as long as enzymes are active.  The professional mash-in is likely to be very homogenous without any dough balls where the home brewer is much less likely to achieve this and it is prudent to mash longer.

[hopfenundmalz]

The iodine test says there is no starch.  It does not tell you what sugars you have produced in the mash.  You can have a lot of long chain dextrines, pass the iodine test, and have wort that is not as fermentable as it could be.

Basic Brewing Radio did a test and show on the mash time.  The longer mashes produced beer that tasted better to the panel.  Too lazy to find the link this morning.

[greatplainsbrewer]

FWIW I did an iodine test on a batch of APA I brewed two weeks ago.  I'd run across an article (not from Stone) that basically claimed that domestic malt converted in a hurry- less than 30 minutes.  I did not show any starch at twenty minutes (Briess two row + C40 + wheat @152F).  I didn't see any disadvantage to letting it sit the full hour so I left it alone.

Just wondering- fully modified malt would convert faster than less modified?

[nateo]

I usually mash for 30min, then vorlauf and run off, which takes another 10-15min. I used to do iodine tests, but I can't really "read" them well, so I just taste the wort. If it tastes sweet I run it off, if it still tastes starchy I leave it longer. I doubt I get "100% conversion" this way but I don't have any issues with starch haze or the like, so it can't be too bad.

It seems the quality of malt available is so much better than it was 10 years ago that a lot of the rules-of-thumb about mashing don't really apply anymore.

[hopfenundmalz]

Just wondering- fully modified malt would convert faster than less modified?

It has more to do with the DP of the malt.  North American malts have very high DP, as they were made to work with high amounts of adjuncts.  Some German malts are not so high in DP, due to the nature of the barley variety, and no need to convert adjuncts.

I have made beers with all munich malt that would not pass the iodine test after >30 minutes.  I would think those are fully modified, but the kilning to get the darker color degrades some of the enzymes.

Someone with a high amount of knowledge on malts can chime in. 

[malzig]

Here's Kai's data from a conversion experiment showing that, while the iodine test was negative at 30', he didn't get full conversion until 60'. 

That doesn't even take into account that fermentability is continuing to be set during that time, which can lead to under-attenuated or worty tasting beer.

Some are as short as 10-20 min at 157F followed by a mash out step.  What are the effects of this?  Will this add substantially to the body of a beer?
I have often felt my beers are sometimes a bit thin despite higher mash temps.  Is this something worth considering or am I merely going to sacrifice overall yield?  Any thoughts?

Mash temperatures that high should solve any thin body problems you are having, even if you mash longer than 60'.  Have you ever tried mashing at 157-162°F?

When they mash in, how long does that take. 20 minutes? More?

How long does it take them to mash out?  I think they have a 200 bbl brewhouse, but it has been a few years since I was on that tour.  This could take a while to raise the temp.

This often explains the short mash times used in professional breweries.  By the time they mash in and mash out the time at conversion temperatures often end up being 60' or more.

[nateo]

Malzig: Thanks for the link to Kai's experiment. My efficiency is consistently 70%, +/- 1-2%. I might try a longer mash next time and see if that boosts my efficiency.

I remember hearing an interview with Dr. Bamforth where he talked about dextrins and beer. In a blind tasting, they doctored a light lager with pure dextrin. It took a huge amount of dextrin, like more than you'd ever see in wort, to get even a slight change in the apparent body or texture of the beer.

Proteinases should be active up to 155*F in the mash, so I wonder if, with highly modified malts, the effects of high temp increasing body are the result of less protein degradation, and don't involve dextrins at all. 

[bluesman]

When they mash in, how long does that take. 20 minutes? More?

How long does it take them to mash out?  I think they have a 200 bbl brewhouse, but it has been a few years since I was on that tour.  This could take a while to raise the temp.

This often explains the short mash times used in professional breweries.  By the time they mash in and mash out the time at conversion temperatures often end up being 60' or more.

I believe that this is most likely the case for pro-breweries. In an effort to salvage cost (because time is money), they shorten the saccharification rest and gain complete conversion during the ramp up to mashout temps.

[nateo]

I'm not sure if it takes all that long to dough-in. I've read of breweries spraying their grist with strike liquor as it comes out of the mill. It then falls into a pre-heated tun. The limiting factor would be how quickly they can crush their grist. Some of the serious grain mills like a Kuenzel can crush 500lbs/min.

For a 10bbl batch of 1.045 beer, you'd need about 500lbs of grain. If your mill can grind at 50lbs/min, that'd only be 10min of dough-in. Most breweries try to ramp at 1*C/min. If you ramp from 70C to 75C, that should only take 5min. If they can only ramp at 0.5*C/min, that would take 10min.

10min - Dough in
20min - 70* C rest
5-10min - Ramp up to 75*C
? - run-off

So it could definitely extend the effective stand time, but not necessarily by all that much. Of course there are a thousand breweries who approach this a thousand different ways, and I have no idea what Stone actually does.