Mash rests and Diastatic Power

[citizensnips]

Kind of have two queries here, if anyone could shed some light that would be great.

I've been doing some reading on making a Japanese style lager beer and have come across the need to add a good amount of rice to my beer. Here's the recipe I'm looking at http://www.homebrewtalk.com/showthread.php?t=12143
What I can't understand is if one were going to add 1kg of rice to their mash once it has been boiled, geletanised and broken down......why then does it need to have a protein rest. The author of this post writes it's necessary 'because you need to condition your rice sludge before sacc rest'. Isn't this the entire point of boiling it prior to the mash?

Secondly am I going to have enough enzymes in my mash to convert 1kg of rice using 3 kg of 2 row (I would be doing a bigger volume however ratios would be the same).
I brewed with raw wheat some time ago and ruined a batch from not fully converting the starch so don't want to do it again.

 

[MHB]

25% rice shouldn't be a problem for any good quality pale malt (some of the most adjunct rich brewers use over 40% - with 6 row malt).
I would add 10% malt grist (100g/kg of rice) to the cold rice and water then heat it slowly (at say 0.5-1oC/minute rate of rise) with a lot of stirring all the way till it comes to a boil, the enzymes in the malt (mostly talking about Glucanase and Proteases) will really help to liquefy the rice.
Allow to cool to your strike temperature then blend it in with the rest of the grist and strike water. If the rice is fully gelatinised you really shouldn't need to mash in any cooler than you would for any other all grain brew.
Mark

 

[Bribie G]

MHB would be the guy to contribute here if he's reading.... I believe the traditional cereal mash (combining the rice with some crushed base malt) used by American brewers such as Budweiser starts off fairly low as there are enzymes that break down the "capsules" that enclose the starch granules of the rice or maize even after gelatinisation, making the starches more available, then they raise the temperature during the mash up to a final boil.

In practice, I often do rice lagers and find that just boiling the rice to a porridge and stirring in some base malt at 72 degrees does a fine job of "preconditioning" the rice and breaking it down using the alpha amylase of the added malt. Then I tip into the main mash. I'd guess starting the cereal mash off low might have some commercial advantages if you are brewing hectolitres of Bud or Corona etc.

As for diastatic power, Aussie malts such as BB or JW pale malts have masses of power, wouldn't worry. I also had the opportunity to talk to Thomas Weyermann a few years ago at a masterclass and he said their Wey Pils malts will convert up to an extra 40% of adjuncts.

I believe UK malts such as MO are a lot weaker, maybe only 15 to 20%

Edit MHB beat me... right on cue :lol: :lol: :lol:

 

[citizensnips]

Awesome replies fellas, thanks very much. Now all I've got to do is find this Japanese rice!

Cheers

 

[Bribie G]

I use supermarket rice, funnily enough I'm preparing a post to put in the database: this Aussie rice lager currently on tap is actually 4kg of BB Pale and a kilo of plain old IGA long grain.

 

[Coodgee]

I use supermarket rice, funnily enough I'm preparing a post to put in the database: this Aussie rice lager currently on tap is actually 4kg of BB Pale and a kilo of plain old IGA long grain.

rice lager.jpg

how is it? does it taste like asahi?

 

[Bribie G]

More like the old Carlton Draught as it has a few hops in it.

 

[Nurple]

I use supermarket rice, funnily enough I'm preparing a post to put in the database: this Aussie rice lager currently on tap is actually 4kg of BB Pale and a kilo of plain old IGA long grain.

rice lager.jpg

Looking forward to the recipe mate