Basic brewing questions

[RichardM]

I was wondering if a recipe calls for a 90min mash & 90min boil, vs. 60/60, is it really critical to the outcome? This would be in reference to brewing a bock, but was wondering in general. It will also be brewed using biab method. I understand that a fine crush and maintaining a good temp will yield a good conversion well before 90min. I’m not sure about how the extra 30min boil affects the results. Other than yielding more water loss, what does the extra 30min do for the process? If I just stuck to 60min boil would the outcome be different assuming I accounted for the water correctly?
Also on a similar note, what effects does an aggressive boil vs a low boil have?
Hopefully these aren’t too basic of questions, just trying to understand the process better.

 

[Lefou]

A bock, eh?
Well, it's a style with a higher gravity, so a couple of reasons for an extended mash.
You'll likely have more grain and this means a higher likelyhood of lowered efficiency. You'll want to consider a thinner mash than usual for a longer period of mashing time to get a more fermentable wort. If you have a thinner mash done with a more vigorous boil for a longer time it allows for caramelized color and Maillard products to be created. It increases your boiloff levels and yields a portion of darkened sugars (dextrins) that will enrich your bock wort.
A longer boil will affect your hopping rates so take that into consideration, too. I typically use a 60min boil time as a reference for hopping levels. Mash longer, boil shorter.
No real need to do extra work if you have a good mix of well-converted Munich malt, but you do need to make sure your mash yields an acceptable gravity for the boil.

 

[oakbarn]

I like to Mash for 90 and Boil for 90. Adds an Hour to the Brewday. The Boil could be cut unless the Hops call for 90. Mashing longer is better. I tried 60 and was not reaching my desired SG.

 

[Qhrumphf]

As far as mash time, it depends on the temps. If you're doing a step mash, it's seldom gonna follow the 60/90 single infusion time norms. Lower mash temps generally will take a bit longer to convert to appropriate fermentability than a higher temp will (alpha amylase will hack apart starches to its limit much faster than beta amylase will snip off all the maltose that it's able to).

Longer boils will both concentrate your wort (which is helpful to get maximal efficiency on a bigger beer), and darken it a bit, and theoretically form a bit of flavor in the process. You won't see much of that between 60 and 90 mins, but if you extend to several hours it becomes pretty apparent.

As far as boil *strength*, most homebrew boils are overkill. As long as you're getting surface exchange and are boiling off ~5% over an hour, you're fine. The 15-20% boiloffs most homebrewers (especially those using propane) aren't necessary (and from a flavor stability standpoint could actually be detrimental). BUT. More boiloff = more concentrated wort.

With big beers, I prefer to mash them a bit thicker. A) help them fit in the mash tun and B) boosts the efficiency with extra sparging so I don't take as big of an efficiency hit. I use a traditional setup, not BIAB, so your process may differ there.

 

[RichardM]

This bock recipe is a little different from my past recipes. It calls for a 90min mash at 152 in 3gal of water then sparge with 3 3/4 gal @ 168 deg. Boil 90min reducing volume to 5 1/4 gallons or less. I was planning a full volume rather than sparging.

 

[CascadesBrewer]

I was wondering if a recipe calls for a 90min mash & 90min boil, vs. 60/60, is it really critical to the outcome?

It is a good question. I suspect there are others like me that do things because "that is how I learned" but I don't fully know the impact. I generally mash for 60 minutes for 90% of my beers and I occasionally do a 90 minute mash for beers with a lower mash temp and/or beers with a good amount of adjuncts. I brewed a beer last weekend with a ~150F mash temp with 3 lbs of Flaked Rye and I let it go for 90 minutes. I broke out my iodine and did two tests and did not get any purple in the test at 60 minutes (and only a little bit at 20 minutes). I hear talk about people moving to 30 minute mashes, but I don't mind just letting the mash sit while I fix breakfast, fill out my recipe sheet, run an errand, etc.

I almost always boil for 60 minutes and I plan my water around a 60 minute boil. A search turned up a few interesting articles about Maillard reactions and some beers with 4 hour or longer boils. At some point it would be interesting to play around with a 2 hour boil...or a 30 minute boil...and see the difference for myself. I could see where a long boil would be good for high gravity beers...but I could also see just throwing an extra lb or two of grain instead.

 

[Calder]

20 to 30 minutes and your mash is done if you have plenty of well modified base malts. If Munich is the base malt, you will be low in diastatic power, and it will take longer. If I were mashing just Munich and some specialty malts, I'd probably go an hour. If there were a few lbs of 2-row or Pale in there, I'll be done at 30 mins.

No reason to boil longer than 60 minutes unless you have a significant amount of Pils (to drive off DMS), or have a high volume of the liquid to boil off after the mash. Only need to boil for 60 minutes in many cases for the hop utilization. I have done a number of 30 minute boils with no issues.

Remember, a lot of recipes that you see (on-line, magazines, and even in brewing books) are just recipes that people have done and been successful with (not sure of the 'successful' part of my comment). So the recipes are just what was done in that instance, often the 'standard' procedure of the recipe creator; not necessarily the only way to do it.

I think 90 min mash and 90 min boil are both over-kill. I suspect you will not have any discernible difference if you did a 60/60 process.