Multi-step infusion mashing/decoction - is it necassary?

[Manx Guy]

Hi my learned firends...

I'm about to venture into the world of AG brewing and in preperation I have doen lots of reading up on the subject...

I have read 'How to Brew', BYOBRA, BBLTYB, The complete Homebrewers compendium, Designing great beers etc etc.

Now my question is this - most of these books with the exception of BYOBRA advocate in most instances using a multistep infusion mash or sometimes a decoction.

I note a lot of opinion on here that with todays highly modified malts a single temp. infusion mash should provide me with a fermentable and haze free wort and beer.


Are there any instances when I should consider doing a mulistep or decoction mash? and if so when?

I will be doing a porter for my first AG brew followed (most likely) by a Discovery or TTL clone from GW's excellent BYOBRA (I've done several extract recipes from the book to date)

After I have done some successful brews I'd like to atttempt to brew some beers that I like but cannot get commercially namely Oktoberfest and Vienna style lagers - these styles seem to require one or other method of mashing in all the receipes I've seen (one for Modello Negra I posted on here to get peoples views)
I also fancy trying Dave Lines Grolsch clone ( I think Cheschire cheese tried this version)
I would welcome peoples thoughts and especially those who have experience of trying these brews using both methods.

Thanks in advance.

Guy

[steve_flack]

There are certainly things that you would get from a multistep infusion if you were doing certain beers. For example you could increase the amount of ferulic acid in your wort by mashing at around 45C for a short period (ferulic acid is the precursor to the clove flavour in wheat beers). There are other reasons for doing it as well.

Are they necessary? Probably not. You definitely don't need to do them for anything British. The majority of British brewers will be using a straight single temperature infusion mash.

Do you need them for lagers? Many continental brewers use a step infusion rather than do a decoction as it's more energy efficient and less time consuming (read 'cheaper'). From a technical standpoint there is no reason to do a decoction anymore but some brewers say it gives something to a beer to can't get any other way - others would just use a bit of munich or aromatic malt instead.

Step infusions aren't that difficult to do and don't take that much longer than normal single infusion mash. I've done lagers using a Hochkurz mashing schedule (30 mins at 63C then 30-45 minutes at 70C) for example. Not sure it added much but it didn't take long.

[Manx Guy]

Interesting....

Thanks Steve!

I've seen the various calculations for step infusions and on the face of it they dont look to difficult. It seems that if you start with a thichk-ish mash (2:-2.5:1) then mash tun space isnt much a of a problem for lower gravity 23litre brews...

It seems to be a case of adding strike water at the desired starting mash temp. then adding various ammounts of boiling water to increase the temp. of the mash in the desired amount of stages...

One curious version of 'step mashing' I have come accross is in the 'How to Brew' book. as for an Oktoberfest beer the suggested mash schedule is:

30mins at 60C
30mins at 70C

What would be the benifit of this over a 60 min mash at 65-66C ?

Cheers!


Guy

[steve_flack]

The idea behind the two stages is that they favour one or other of the amylase enzymes. The length of the lower temperature rest determines the fermentability and the second rest is eseentially there to complete starch conversion.

As for mash thickness. It is apparently usual in German brewing to have much thinner mashes than in UK brewing. They tend to favour 3.5-4.5 L/kg so ending up a bit thinner than usual (due to additions of boiling water) isn't really a problem. The reason given for the preference for thinner mashing is that is means less sparging and so less tannin extraction. Maybe it's a similar idea to why people say no sparge mashes give better flavour? It probably is also better for the German system where they have a separate mash and lauter tun.

[Manx Guy]

Thansk again!

Very informative! I'll be sure to post my 'brewday' when I get experimental with multistep mashing....

However it'll definately be British style single step infusion to begin with.... Mainly so I get used to the entire process ( mashing, sparging boiling and cooling etc etc.)
There are also plenty of recipes I wish to try out from the BYOBRA book


Guy

[raiderman]

Not much to say, because steve has said what you need to know. For british beers you just need an infusion mash, for lagers at most a stepped infusion is all you'll need. Decoration and stepped infusion mashes were developed because continental malts weren't as suited to brewing and different techniques were developed to overcome the problems this gave rise to. In theory modern lager malts should produce good results with a single infusion mash. I find I get better results with lager if I include a 30m protein rest at between 50/55c and then raise and mash out for 60m at around 67c or whatever temp is called for. It doesn't really prolong the mash and it may just be superstition on my part but thats how I do it. If you brew lager alternate the approach over your first two batches and decide foryourself

[crookedeyeboy]

Yup Steve's got it covered! I just thought I would add that I was under the impression step mashing came from Europe due to their malt being very poor compared to UK malt, its still the case in some places.
Theres another thread on here about using Lager malt as a Pale malt which back in the day I suppose would have been a no no due to it NEEDING to be step mashed to convert the sugars but these days our UK malt is so well modified that there is no need...Obviously theres the case of personal taste and the flavour of lager to pale ale.

[raiderman]

at the risk of crossing threads I was drinking in Todmorden over the weekend and came across a range of pale ales brewed using lager malt and cascade, of which the 7% had a great flavour. Thats the fun of home brewing, you can mix styles and ingredients and come up with your own unique style

[Manx Guy]

Thanks guys!

very helpfull...

Once I'm back from Sweden I get a brew on!



Guy

[Invalid Stout]

One other important reason decoction mashing was done is that it was possible before the thermometer was invented. Without a thermometer, you can tell blood heat (when the water "feels hot") and you can tell boiling point. A triple decoction gets you reasonably close to the temperature still used for mashing today. Mash in at about 37º — take a third of the mash and boil it — add it back and the whole mash comes up to 50-something. Do it again, and raise the mash to 60-something. Do it once more and you're at mash-out temperatures.

[Manx Guy]

One other important reason decoction mashing was done is that it was possible before the thermometer was invented. Without a thermometer, you can tell blood heat (when the water "feels hot") and you can tell boiling point. A triple decoction gets you reasonably close to the temperature still used for mashing today. Mash in at about 37º — take a third of the mash and boil it — add it back and the whole mash comes up to 50-something. Do it again, and raise the mash to 60-something. Do it once more and you're at mash-out temperatures.

Hi, I had heard that decoctionmashing predated the thermometer, but hadn't a clue how using decoction would be benificial...

However thanks to your post it now make s alot of sense!
I had read up on how infusion mashing helps correct temprature of the mash (by adding hot water) but of course you need to know the temp of the mash before you can do the calculation! Unlike decoction where as you say you move a thiord of the mash and boil it before adding it back to the MT...

Very informative, thanks!

I am itching to get my first AG brews under way now - 1st up a Porterfollowed by a Pale ale (most likely TTL or Discovery)

Cheers!



Guy

[Cheshire-cheese]

After my rather fraught stepped mash with the Grolsch clone and the single temperature mash for the subsequent lager. I'd stick to the latter approach. So much easier.

[dedken]

I will be doing a porter for my first AG brew followed (most likely) by a Discovery or TTL clone from GW's excellent BYOBRA (I've done several extract recipes from the book to date)

Hi Guy,

I've just tasted my first AG which was a cross between a Discovery and an Explorer. It's come out astonishingly well (after only 1 week in the bottle). I used a single step mash and then did a re-mash in place of sparging. Didn't quite hit my expected gravity but it still tastes marvellous with good mouthfeel and head retention. I can send you my notes if you're interested. Best of luck!

K