I do BIAB outside even in relatively cold weather.
I’ve often wondered what would happen if one aimed at the higher end of the mash spectrum to get a more richer, dextrinous wort, but perhaps due to an emergency had to leave the kettle alone during the mash process for so long that the temperature of the wort fell completely through the low end of the mash spectrum to say even 140 F.
What kind of wort would that produce?
When you start at the high end of the mash spectrum does that “lock in” the less fermentable longer molecules or must one maintain that relatively higher temperature for the duration of the mashing process?
As long as you are still beginning the mash at a reasonable temperature like 158 F or something, you’ll still get good wort, but it might not be quite as fermentable due to accelerated denaturing of the beta amylase. However your efficiency could be expected to be increased by several percent.
If I were brewing in the cold as you are, I would do pretty much the same thing. Maybe start at 156 F, then just let it fall if it wants.
Regardless, most of the enzymatic activity occurs within the first 40 minutes anyway. Any time spent beyond 40 is a “bonus”.
Do your beers have body or mouthfeel problems? Too thin? Then you might benefit from a higher mashing temp. But just boosting temp in a quest for ‘richer and dextrinous’ might not work very well. I started out brewing like that and appreciated the beers, but have since found that targeting more fermentable wort produces a more drinkable beer for me. Richness isn’t necessarily lost when you drop your mashing temperature.
In fact I think malt flavor has more punch when cloying sugars or flavorless dextrins don’t get between it and my tongue. “Dry” and “malty” are not opposites.
My question was theoretical. I was reading about the two amylases and just wondered what would happen if you let the mash temp drop through the full range.
I normally mash in at 153 F, wrap my pot with an old pair of insulated coveralls, and my mash temp will normally drop by only about 3 F.
I’m satisfied with my beers, but I’m always tinkering with the recipes.
Beta amylase is more wimpy than alpha amylase. Temperatures around 155-160 F kill off most of the beta within about 40 minutes; meanwhile, alpha is most active at the same temperature and is working its butt off, not dying off as quickly as beta. The net result of a mash that starts on the warmer side is a very efficient mash… but not quite as fermentable as it might be if maintained at lower temperatures of say 145-150 F. Both alpha and beta are very useful, but behave a little differently. The sweet spot, of course, where they both work really well, is about 150-155 F. (Someone might want to tweak my numbers a little bit, and that’s fine, but they’re reasonably close. The whole dang thing is a spectrum anyway – beta doesn’t suddenly all die above 155 F – it takes time – and alpha is plenty active already even as low as 145 F, etc.)
I’m relatively new, and also use BIAB (where the final “B” is a stainless mesh basket.) For Belgians, I’ve been running the full temp range from the other direction - starting low, then raising mash temp in several steps until mash-out. I have read that with current “modified” malts, this is is totally unnecessary, but it works for the Trappist brothers, and why not? It’s not more work, because I’m using a pump and electric heat. The step mash process is more repeatable than it was with gas, and I can use my basement without asphyxiation.
I’ve also been told that with step mashing, I should remove Carapils and other dextrin malts from recipes. I’m a little less sure what to think of this. If I substitute in more base malt, it seems to drive the gravity slightly higher, and I don’t notice any difference in the head or foam. Maybe I’m not perceptive enough.
I think you are close in grasping the points above, but perhaps some further clarification could help:
The beta amylase once denatured, stops the work of breaking the chains of sugar, leaving only the alphas to do what they can do, which they can actually do more than betas and quicker, but they are helped by the betas on breaking down specific starch types. You can google this for more info and get a more technical evaluation.
As to Carapils, I use it for flavor (as a light crystal malt) rather than the misconception of aiding foam or mouthfeel (it actually is foam negative in effect).
But in the end, try it for yourself and reach your own conclusions - Cheers!