The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Rye Amylase

foolishpoolish's picture
foolishpoolish

Rye Amylase

I have been learning about the practice of pre-gelatinization (scalding) of rye in the preparation of high-percentage rye breads.  One thing confuses me, however, with regards to the intended effect this has on the final dough. As I understand it, pre-gelatinization is a process typically used to make starches, in a given grain, MORE accessible to amylase (for example in brewing) In a wheat flour & water mixture the amylase starts to denature at temperatures above about 150Fl. In brewing (where diastatic malt is ADDED) careful control of this temperature during the mash can determine the ratio of alpha to beta amylase and thus fermentable vs. unfermentable sugars (for brewer's yeast). 


However in the case of rye, I understand that rye amylase is more heat-stable. I would think gelatinization is precisely the OPPOSITE of what one should be striving for  since the integrity of the pentosans in the rye is the major factor in preserving structure and preventing gumminess. Making them MORE vulnerable to amylase, earlier on in the 'production' process should surely be avoided? While the acidity of the rye sour should control the effects of amylase somewhat, one is still left with the question as to why scalding is done at all? A sweeter end result perhaps? 


All of which leads me to think that scalding the rye, in order to be effective, must be carried out at a fairly high temperature in order to denature the rye amylase...but what temperature might that be?  What proportion of the total rye flour (say in a 100% rye bread) should/could be scalded? Are there additional benefits from scalding rye that I am missing here?


If anyone has knowledge in this area, I'd be most appreciative of your input.


Thanks


FP

suave's picture
suave

you're confused because you think that scalded flour is added directly to the dough. It's done, yes, but that's really a shortcut usually taken in large scale production to reduce the costs.  Traditionally, though, scalded flour was used to feed the final build.

dghdctr's picture
dghdctr

Hi FP,


Who's instructing you to scald flour, either personally or in their writing?


--Dan DiMuzio

hansjoakim's picture
hansjoakim

There's a thread at Dan Lepard's forum about scalding rye flour. Here's another interesting thread about the same topic: Clickme.

foolishpoolish's picture
foolishpoolish

Mike (Suave): Interesting, so basically scalded flour is used to feed the rye sour. You said 'final build'...does that refer to the last stage of a detmolder process?


Dan, Hans: Yes, Dan Lepard's 100% rye was the first time I'd heard about scalding rye flour. However I've seen mention of it in commercial products such as these: http://www.amberbakery.co.uk/bread.php  which is a whole range of 'scalded rye' breads. There's also a recipe here on the fresh loaf for borodinsky rye: http://www.thefreshloaf.com/node/9459/100-rye#comment-48854


'Scalding' seems to be have been the subject of this research: http://www.cababstractsplus.org/abstracts/Abstract.aspx?AcNo=20053048913


Perhaps scalding is a process really only of benefit for large-scale commercial application?...although I'm still intrigued as to why and how.


FP

suave's picture
suave

FP, that it is a multistage build doesn't automatically make it Detmolder, Detmolder refers to a set of very particular fermentation schedules which can have 1 to 3 stages.  The recipe for borodinskiy you linked is multistage, but most definitely is not a Detmolder, in fact it shows rather nicely, how the scalded flour is used to create soured mash (sponge) which makes the bulk of the final dough.


The chemistry of using mashes is complicated, but the basic idea is that it quickly provides large amounts of fermentable sugars (notice how the technique is popular in the parts of Europe not known as sugar-producing regions :)), which helps offset sourness of rye starter and improves overall taste and aroma. 


Mike

foolishpoolish's picture
foolishpoolish

Thanks for clarifying that Mike. So the scalded flour is used in a similar way to a mash in brewing (ie to aid starch saccharification)


I wondered if there were any other benefits (adding 'strength' etc.) but it would seem not.


With regards to Detmolder (another topic entirely, I confess) I've had trouble reproducing the process. To follow it exactly would require a greater degree of temperature control than I can provide in a home environment.


FP

dulke's picture
dulke

I've been meaning to try Lepard's recipe for rye, as it looks very much like a rye bread I remember trying once that my dad and one of his contemporaries waxed eloquent over. They were born in Lithuania and said that the bread was "plikyta", i.e. scalded. I had never found anything that seemed to fit the bill until I saw his recipe. I think the bread they wrere referring to was 100% rye, but if I can get close to it, I owould be happy. They described it as a gentled rye.

nicodvb's picture
nicodvb

Hi,
what about the fridge? Does rye still develo amylase when in the fridge (although, probably, at a slower pace)?

suave's picture
suave

You are missing the point.  The peak of amylase activity is in the 130-150 F (55-65 °C) range, so the damage predominantly occurs during the baking. 

Yippee's picture
Yippee

Here's what she said:



controling the rye amylases?  I was just reading (Hamelman's Bread p 47) that Not until they reach 176°F would heat destroy them.  By heating them only to the gelatin stage, the amylases would be fully activated and a great deal of risk is added.  (Could be the reason behind the Northern European rye recipes asking for boiling water added to rye... interesting.)     



in the post of my first sourdough rye bread. Hope it answers part of your question.


Yippee

nicodvb's picture
nicodvb

Hi,
where is amylase concentrated in rye? In the endosperm or in the bran?
Thanks.

dghdctr's picture
dghdctr

The minerals in a wheat or rye berry are concentrated in the bran, but the amylase is generated in the endosperm as the berry nears ripening.  And rye flour has more amylase pound for pound than most wheat flour.


Why do you ask, Nico?


 --Dan DiMuzio

nicodvb's picture
nicodvb

Hi Dan,
thanks for your answer.
I asked it because I'm trying to understand if a hot soaker with boiling water (in order to develop the sweet taste) is equally effective with white/sifted rye flour as with dark flour.
I always add a good portion of hot soaker in my breads because I like the added sweetness, but the only time I did it with white rye flour I perceived a lesser sweetness, while jugding from your answer I guess should have perceived at least the same.

Nico

ehanner's picture
ehanner

Last year, Jeremy Cherfas started a thread on Dan Lepard's Black Pepper Rye and ended up having Dan himself chime in along with many of the whole grain experts including hansjoakim. If you haven't looked at this thread in a while, it is an excellent thread concerning the gelatinous properties of rye flour.


I have made Black Pepper Rye several times and have sorted through the issue of just how hot to get the hot water/rye mix in the process of scalding. It makes a huge difference in the dough if you bring the mix to a boil. The amount of additional water to achieve a workable dough is remarkable. The rye sucks up an incredible amount of water when the scald reaches boiling.


On the other hand, I discovered that if I heat water to 185F and pour it over the rye, I get the sweetness with out the hydration issues.


Eric

nicodvb's picture
nicodvb

Very interesting thread!
For the cronicle I always do the pour, never the boilup/roux, exactly because I want the maximise the effect of amylase on the scalded flour to develop the sugars, relying on the acidity of the levean to disactivate it for the sake of the structure of the bread, i.e. I'm trying to combine the best of both worlds.

I was wondering if there's a temperature after which the alpha-amylase is definitely "dead", that is it can't work anymore even if the temperature of the dough falls near 65°C where amylase is most active.
Doing some calculus I got to the conclusion that in order to reach an initial temperature of 75°C (a bit below the 80°C that seems to be the limit) you have to combine
N gr of flour at 20°C
with M=N*11/5 gr of water at 100°C
assuming, of course, that the temperature of the dough is exactly the weighted average of the temperatures, that is
(M*100 + N*20) / (M+N)
that is not a given, meaning that the equation may not apply at all and that my calculus is completely without bases.

M*20 + N*100 = T*(M + N)
M*20 + N*100 = T*M + T*N
N*(100-T) = M*(T-20)
N = M*(T-20)/(100-T)

to get T=70 with M=100, N=166

ehanner's picture
ehanner

Nico there are other variables to consider that I think make it difficult to reduce this to an exact formula for every situation. The amount of mass in the bowl that contains the flour, how quickly you incorporate the water to name a few. If you experiment by warming water or coffee, in the case of the Black Pepper Rye, to a pre determined temperature and mix it into the flour, you will find a temp that suits your needs. It will take trial and taste. Which is the tough duty of the adventurous baker I know you are.


Eric

ananda's picture
ananda

 Hi,


Eric, you are spot on with the use of a "boil-up".   It really aims to provide the essential take up of extra water.   My all-rye formula generally calls for 85% hydration.   Using a technique of adding water on a rolling boil to a portion of the rye flour achieves gelatinisation.   Cool this mix down, and add it to the final dough, and final hydration levels sore.


Best wishes


Andy