I am primarily interested in Stepped Mashing because I have a Braumeister and can easily do 5 temperature steps/rests on top of a set mash-in temperature.
This discussion could be applicable to RIMS or HERMS or homemade variants of temperature controlled wort production. Even BIAB with a direct heat source under, or in the mash could be in the same category.
This is not a topic about decoction mashing.Infusion mashing
- mash is heated directly or hot water is added. It is only about changing the temperature of the mash. Temperature mashing/ step mashing – much the same definition.Decoction mashing
- a portion of the cereal/grain mash is removed and heated before being returned to the mash. This can modify flavours and colours as well as a change in temperature of the mash.
I am posting what I have found for the purposes of discussion. It is a summary and I invite comment. I am not going to try to discuss all enzymes and the processes of interest or the whole science of mashing. I am going to try and keep this simple (so am not mentioning attenuation or efficiency); it may require you to do some reading or research of your own. If you know something I have said to be wrong, please post so that we may all learn. It is a topic that continues to be confusing.
The science of mashing is quite complex and my basic reading has led me to many contradictory statements, facts and figures. Different authors quote different temperatures as being optimal for particular enzymes active in the mash. These authors even use different names for the same processes, for example:
• Amylase Rest vs Maltose Rest vs Beta Amylase rest (3 names for the same temperature rest)
• Amylase Rest vs Saccharification vs Starch Conversion vs Glyco-protein Rest vs Alpha Amylase Rest. (5 names for the same temperature rest).
In some instances, there are different processes that the authors are concerned about that occur at the same temperature and thus differing names are used. Sometimes it just seems as though there is no standard naming convention.
It would seem that the biggest influences on the enzymes at work in the mash are pH, temperature and duration of the temperature.
Other factors include
• water chemistry (which I will not touch)
• the type of malt
• milling of the grains
• water to grist ratio
• diastatic power or enzymatic power– the hotter a grain is kilned the less it has
• dark malts increase mash pH.
• many other factors too.
A reasonable read on the above factors can be found at: http://braukaiser.com/wiki/index.php?title=Effects_of_mash_parameters_on_fermentability_and_efficiency_in_single_infusion_mashing
I want to specifically look at Temperature and Time (with only hinting at pH) as these are the factors I want to use in Step Mashing. I have tabulated some of the information that I have collected.
The table should be read horizontally.
The values in the light blue section on the right side of the table are minutes. It shows how many minutes, for a particular beer style, that the mash could be kept at a particular temperature (listed in the vertical column of Optimal Temperature)
The biggest thing is, what do you want to achieve with each step of the mash? Hopefully some of this information is in the table.Acid rest:
“The acid rest is not used nowadays because it can take several hours for this enzyme to lower the mash pH to the desired 5.0 - 5.5 range” John Palmer, How to Brew.
I like the ‘idea’ of starting with an acid rest because it is quicker for your mash liquor to reach these temperatures for mash in. If you are doing a wheat beer or a beer with >25% rye, oats or undermodified malts, it may be advantageous for you. With these beers and others, if it is done for too long it may have undesirable consequences. Protein Rest:
Seems like a lot of folks refer to “Simple single infusion mash for use with most modern well modified grains (about 95% of the time)” and such quotes about modern well modified grains. These folks say you don’t need a protein rest and won’t even entertain the idea. It seems like most of these quoting folks haven’t tried a protein rest. Some of those that have actually used protein rests swear by them. As some say, Nige included, a short protein rest is not necessary but may be useful none the less. Gimme Sugarz!
You can create a wort higher in fermentable sugars, one that is higher in unfermenatble sugars, or try to produce one that balances the two (66oC seems to hit that mark). Both fermentable and non-fermentable sugars are going to be formed at the optimal temperature for the other, it is just one will be favoured. Mash out:
Raising of temperatures at the end of the mash to stop enzymes working and makes the grain bed and wort more fluid and can prevent a stuck sparge. Any starches rinsed out during the following sparge will not be converted to useful sugars as the enzymes have stopped working, these starches may cause haze in the finished beer. It doesn’t seem likely that a good mash would contain residual starches. A mash out would seem to be important for a mash that contain wheat, oats, rye and undermodified malts. Temperature and time:
Given that the enzymes of interest work over a temperature range (debateable ‘optimal’ temps listed in table) some folks don’t change their actual temps, just the duration at those temps. Essentially each step or temp rest will do something desirable, you just want to change the particular ratios of resulting products from enzymatic activity in the mash. For instance, I stalked Manticle on the AHB forum and note he pretty much uses the same temperatures but just varies times of each step for differing brews:
*actually 1oC lower
You can see that the Saison would favour the production of a greater amount of fermentable sugars than the EIPA.
The Beersmith program says:
Light body = 64.4oC for 75 mins
Medium Body = 66.7oC for 60 mins
Full body = 68.9oC for 40 mins
The literature also supports that the higher temperature enzymes work quicker, so a short rest at higher temps could have more of an affect than you might think. For example, it could well be that for a 50%-50% split of fermentables and non-fermentables in a wort might actually be produced in a mash of 63oC for 45 minutes and 72oC for 15oC (times just plucked out of the air), or the same result might actually be achieved at 66oC for 60 minutes?
I am not wanting to start an anti-step mashing debate. With a Braumeister it is no big deal to step mash, if it is not going to have a negative affect and might
be beneficial, then I am going to do it, just for the heck of it, because I can.
If you use single infusion mashing with a mashout, or decoction mashing, these questions are not for you. If you use temperature steps:
• what temperature steps do you use?
• for how long?
• for what style of beer?