BIAB = shorter mash time needed?

So, I was having a conversation with my LHBS owner the other day, and we got into a friendly discussion over mash times. He asked me how I maintain my temp over the full 60 minutes of mash....to which I responded, I wrap it in a coat or thermarest pad, but generally, I feel that most of the conversion happens in the first few minutes anyways, so if the temp falls a few degrees (say 3-5 degrees) over the course of the 60 minute mash, it isnt really going to have much of an effect if any on the outcome of the beer.

His argument was that if this was truly the case, then commercial brewers would be on to this, and would not waste time mashing for 60-90 minutes if they didnt have to. I really didnt have a good response, other than what I had read on here.

In my defense, I have maybe 5 BIAB beers behind me....all of which have turned out very well. I read a bunch, but have never done any experimenting.

In his defense, he has never BIAB'd....only raising points from a curiosity standpoint....and from a traditional AG point of view.

Thoughts???

 

I hear this a lot both with BIAB and other mashing techniques. My only word of caution is that conversion does not equal wort fermentability.

You can certainly make great beer when losing heat during the mash. In fact, several craft breweries I have visited admitted to losing 5-8 degrees F during their mash. It is important to know your system and design your recipe and mash profile accordingly.

 

That's for sure. The pale ale I mashed for only 10 minutes at 154 had an OG of 1.052 and so far has only fermented down to 1.004.

Wait, what was the question? Something about conversion does not equal fermentability? Maybe that's right, the previous beer like this that I mashed for 30 minutes finished at 1.002.

 

My suggestion is to be wary when people suggest drastically shortened mash times. With today's malting processes it may be possible to achieve conversion in 3 minutes (based on an iodine test) but I think the jury is still out when it comes to how fermentable this wort is compared to wort from 60+ minute mashes. I haven't looked too deep into this but more experimentation may be required before shorter mashes can be claimed a good or bad thing for home brewers. I found some info related to this over at Braukeiser's site, here.

I'm planning to stick to my 60-minute mashes for now.

 

Haha, good point RM-MN. I am not saying you can't get the same, or similar FGs, just saying that conversion and fermentability are not necessarily the same thing. I think many people assume a clean iodine tests means the mash is complete, but sugars can still break down into smaller chain sugars and affect the wort's fermentability. Maybe that matters, maybe it doesn't. Certainly other variables begin to enter the equation as well.

 

Something else to think about for the retort to your LHBS, would be that a big brewery would require more grain as well as a massive bag to do a normal sized batch. BIAB is great for home brewers becuase it accomplishes a similar task with less equipment (I did say similar not exact!) In my learning expierience, which is extremely limited, I was under the impression that the longer mash time was to convert the sugars into smaller chains or something like that so that you get more fermentable wort. RM-MN brings a lot of good points into this with experimenting and it would be interesting to dig through the old chemistry books to make sure we understand the breakdown process. Just a few thoughts! I have been mashing for at least 60 minutes, would love to drop that to 5 minutes if it was exactly the same! Standing by to learn some more (BTW I am taking the OSU Chemistry of Beer Class, unfortunately I hate learning by watching the videos so I have to go back and look at the first chapter again to see if they discuss this in depth!)

 

I wouldn't suggest that you drop to a 5 minute mash but you might try a couple 30 minute mashes and if those turn out like you want, try a 20 minute mash. That shortens your brew day quite a bit. Want something else to experiment with? Try a 45 minute boil and no-chill. Just dump the boiling hot wort right into a bucket fermenter, put the lid on and wait for it to cool. You can expect about a 36 hour wait or maybe a bit more or less to get to pitching temperature. I've only done one that way and did the same recipe with the full boil and conventional chilling before pitching and I can't tell the difference. So many thing to try, so little time....

 

Just to clarify, we are not talking about why commercial brewers are not going to BIAB...BIAB really is limited to relatively small batches due to obvious reasons.

I am more concerned with how fast conversion takes place with BIAB versus more traditional AG methods, and if it is indeed faster...then why? Also, if conversion is pretty much done within a few minutes, then would a drop in temperature over a 60 minute mash really have an effect?

Side note: How fast does conversion take place in standard small batch all grain methods....and how would a temperature drop over time effect these batches as well?

 

I'm certainly not the most experienced with the mashing process since I've only been doing BIAB for 6 months. I periodically taste my wort throughout the mashing process. Since I don't use iodine tests I taste for sweetness to tell if conversion has happened. One thing I notice besides the sweetness is the flavor of the grains. Like a bag of tea, the longer you steep it the stronger the flavors are. I doubt a 5 minute mash would result in the same great malty flavors that a 60 minute mash would. You might be able to go less, like 30 maybe but 5 seems far too short.


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I think that conversion takes about the same amount of time for BIAB as for a conventional tun, about 2 or 3 minutes. The difference in the time is to allow the grain particles to wet through because a dry particle won't convert. The reason I can get the mash done quicker is the very fine grind/crush of my grain. The particles are so small that they wet through nearly immediately. You can't deal with those fine particles with a conventional mash tun, you couldn't get the wort to drain out, so there is a compromise made, larger particle sizes and good husk sizes for making a filter bed are traded against the extra time it takes to wet the particle, convert the starches, and leach the sugars out.

 

Most of the gravity points come from base grains. Do you change the color and flavor effects of specialty grains by going from a 60min mash to 20 or 30min?


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