I'm a 'returning' baker.  I did a short tour of duty at friends' Tassajara-inspired breadshop startup in the early 70's, but hadn't made a loaf since, until my son miracled me Lahey last year.  NKB broke the ice, but didn't cut the mustard for flavor & texture.  So I'm studying Reinhart, Magee, Buehler et al. to up my game.  I have a question that none has answered.  I apologize in advance for how long this post will probably be.

More preface:  I teach university-level botany, including the  physiology and enzymology of the hydrolytic reactions that release stored, polymerized substrates when a cereal seed imbibes water.  Reinhart is warmly inspring in his fascination with enzymes and his  consequent advocacy of pre-ferments.  But there's something about soakers in particular that contradicts botanical dogma.

Imbibition of water by cereal seeds (barley being the longstanding research model here) allows the stored hormone gibberellin to diffuse from the embryo ('germ' in baker-speak) through the endosperm to its outermost aleurone layer where it binds to protein receptors in aleurone cells.  That binding sets in motion a series of biochemical reactions that ultimately result in starch-degrading enzymes being made de novo in, and secreted from, aleurone cells.  Among these enzymes are the amylases familiar to anyone reading this.  Other stored polymers -- proteins, fats, nucleic acids -- are also hydrolyzed by newly syntheized and secreted aleurone enzymes.  So far so good -- Botany 101 cereal seed germination physiology.

As far as I know, these aleurone-synthesized hydrolytic enzymes do not exist in desiccated cereal grains of the sort we mill into bread flour.  They only get made (to be precise, translated de novo from messenger RNAs) in intact seeds that have imbibed water that allowed diffusion of the hormonal signal from the embryo.  This implies that there shouldn't be any amylase enzyme activity in a soaker consisting of flour and milk, soy milk, buttermilk, etc., unless the milk introduces them.  I don't recall any writers claiming that.  So where do soakers' hydrolytic activities come from?  Addition of yeast or diastatic malt changes everything of course.  But I'm talking basic liquid+flour soakers.

On the other hand, if sprouted grains are used in a soaker, and perhaps importantly, if they are gently mashed first, to release these enzymes to better expose the flour's starch to them, then the latter might indeed be acted upon by aleurone enzymes to release simpler sugars (read: flavors) from the flour. (I'm dying to try this)

So why do soakers work?  Starch-hydrolytic enzymes should not be present in them, because the cellular integrity of the seed that is required to initiate their synthesis is destroyed in milling.  Empirically of course, soakers do work.  It isn't the milk: I've used ultrapasteurized (Meijer organic -- good!) milk in my Reinhart soakers with delicious results.  Ultrapasturization oughta nuke any enzymatic activities for sure.  Is my dogmatic view of germination and amylases overly simplistic, ignoring rogue amylases conveniently present in milled grain?  Or are these writers giving enzymes more credit than they're due, ignoring some non-enzymatic, physical process?

Sorry for the verbosity.  Incorrigible.  I have more questions, but they can wait.  Thanks.

A couple of days ago, I posted here about my failed attempt to make a 100% rye bread. I had followed a recipe by Hadjiandreou, and experienced some problems: I had a gummy crumb and flying crust. I received many helpful comments from the users of this community. The "post-mortem" of the bread suggested that the reason for my problems was excessive enzyme activity. There could be various causes for this (e.g. bad flour quality, insufficient acidification, etc.). 

I had checked that my sourdough is acidic enough, and at one bake I actually added extra vinegar, so I was pretty sure acidification wasn't the problem. The flour is stone ground, and I have no way of checking its quality other than baking. (I have 3 kilos of it at home, so I hoped its quality was adequate). One other cause for increased enzyme activity is letting the dough proof at a high temperature for a long time. The recipe calls for mixing the dough with boiling water, which obviously raises the dough temperature considerably. 

I decided to try making 100% rye bread again. I used the same flour, and the same recipe, but made the following changes: 

• Instead of hot water straight off the boil, I used room temperature water.
• I introduced only a small amount of steam in the baking. (Using a plant mister at the beginning of the bake).
• I used an aluminum foil tent halfway through the baked to guard the dough from burning
• I baked at 220C for 50 minutes (30 in the tin, 20 out of it) + left it in the turned-off oven for a further 10 minutes.

Hi.  i'm not sure if this is the right place to post but I'm sure folks who have allergy issues are experts in ingredients lists.  Does anyone know if enzymes ADDED to flour have to be listed in the ingredients on the flour bag (in the US)?  I could not find this info on the FDA site.  Thanks.