Effects of Extended Mashing (ie 5 Hours +)

[smata67]

I am working out the kinks of a new system and attempting to increase my pathetic 60% efficiency I've gotten for the last 40 batches. So I decided to mash for much longer, for a total of about 5 hours. Started at 147F and I'm using a fairly standard plastic rectangular cooler. Well, a week into fermentation and I'm seeing a FG of 1.002! Had a beautiful 3" krausen for five days and it is now clearing up, so it is probably done. Used a good amount of healthy re-pitched Wyeast 1056, definitely over 200B cells in this 3.5 Gallon. This started out as a simple pale ale with a projected 6% ABV and is now looking like 8%. I did undersize the batch some, deciding not to add water to get to 3.5 Gallons, used my old 60% efficiency (got 70%) in BS, and started the mash lower that I wanted due to some temperature measurement issues. So, the perfect storm.

Do I risk getting such high attenuation every time I mash this long, even if I would have started at, let's say, 154F? I realize that mashing higher will make the wort less fermentable, but is that going to be negated by mashing too long? Does a long mash increase fermentability? The five hour period works for me nicely, I get the mash going in the morning and then finish up late afternoon just in time to enjoy the fruits of my last labor. But if I need to shorten this to 2 hours or so to not get this crazy attenuation, I will.

 

[smata67]

3.5 Gallon Pacifica IPA- All Grain
Brew Type: All Grain Date: 3/8/2019
Style: American Pale Ale
Batch Size: 3.25 gal
Boil Volume: 3.75 gal Boil Time: 60 min
Brewhouse Efficiency: 70.00 %
--
Prepare Water (4.79 gal total)
Amount Item Type
RO Water- 5 Gallons
0.50 tsp Calcium Chloride
1.00 tsp Gypsum (Calcium Sulfate)
--
Prepare Ingredients for Mash
Amount Item Type
8.00 lb Briess Brewers Malt (2 Row) US (1.8 SRM) Grain
0.25 lb Carafoam (2.0 SRM) Grain
0.25 lb Caramel/Crystal Malt - 15L (15.0 SRM) Grain
0.13 lb Caramel/Crystal Malt - 60L (60.0 SRM) Grain

 

[McKnuckle]

A long mash increases fermentability only if it's done in the heart of beta amylase temps, like yours was at 147º (and dropping from there as time passed).

If you want to mash long but not have huge attenuation, then start the mash at a higher temperature so you can get some alpha activity - producing longer chain, unfermentable sugars - as part of the conversion.

Of course if you start too high, you'll denature beta altogether and have low attenuation regardless of mash time. So I'm making an educated guess here, but maybe 153-154 is a good starting point for an hours-long mash.

 

[cactusgarrett]

Do you know where in your process you were losing efficiency? This would require a number of grav readings throughout the brew day. To me, by increasing the fermentability you didn't necessarily raise your efficiency in way that matters for all future beers. As in, you don't want them all to finish (nor will all of them finish) at 1.002. To me, you need to evaluate the post mash gravity and mashing efficiency to rule out an issue there, first. If there's a mashing issue driving overall efficiency down, making the wort more fermentable by a lower temp or longer time frame isn't necessarily the fix.

 

[fendersrule]

Let's get back to the basics.

Mashing at lower temps increases attenuation %. The reason is simple, you are extracting more "pure" sugars. It has nothing to do with efficiency. Conclude: Mash temps are not factored in efficiency, but in attenuation.

Examples:

Mashing at 149F gave me 1.007 for my last batch with the same yeast. (partial mash, tap water)
Mashing at 151F gave me 1.010 on my previous batch with the same yeast. (partial mash, tap water)

As you can imagine, if I mashed at 147F, I would expect something about 1.004 FG. You got 1.002, which is a tad lower than I would have expected, but still within the realm of possibility. I've never dranken a 1.002 FG beer, but I suspect that it's going to be very watery. It will certainly get you drunk though.

I don't think longer mashing time has anything to do with this. For anything below 150F mashing, I typically increase my mash times to maybe 1.5 hours at the max just to be sure I got everything, but I don't feel the need to go any more than that, and that's purely subjective. Increasing your efficiency should come from your milling and sparging process.

Don't confuse efficiency and attenuation. Efficiency stops on the measurement of gravity (OG) you take before you pitch the yeast.

60% efficiency isn't pathetic. It's just marginal. If 70% is the "standard" (which I feel it is for home brewing), you're not terribly off. Instead of longer mashing times, I would look into your milling and/or sparge process.

Investing in a refractometer sounds necessary, and will allow you to easily to check the gravity post-mash. You then calculate for your boil-off, and that will give you a good indicator at that point of what your OG is going to be if you continued toward the boiling process. Compare this to what the calculators say. But it's still going to come down to sparging or milling NOT mashing temps.

With all that said, lower mashing temps give you more alcohol, but it doesn't necessarily give you a better beer.

A beer mashed at 155F and a beer mashed at 147F should produce the same OG. However, the beer that was mashed at 147F will produce a much lower final gravity, therefor, have a substantially different ABV. But NONE of this has anything to do with the term "efficiency".

 

[Smellyglove]

Are you mashing this long, and are able to cut it down to two hours because that's how you spend the hours through they da, or is it just because you felt that 60% ME is low, and tried to bump it?

If it's just because you tried to bump efficiency, then you don't need to mash this long, you need to find out why you're getting lower than average efficiency, and remedy the problem at the root. It can be technique, crush, some due to equipment and most likely a mix of everything. Unless you're mashing directly on top of a big stone without a mashing vessel, you shouldn't need to mash for several hours to get over 60% ME.

 

[schematix]

You'll get better efficiency if you mash higher. You probably aren't gelatinizing all the starches.

I consistently get 100% conversion efficiency, with 75-80% attenuation doing:
144F - 20 min
148F - 20 min
162F - 30 min
172F - 10 min

With steps it completes right at the 2 hour mark.

 

[fendersrule]

Can you explain more about how you get better efficiency by mashing at higher temps? I don't think that's correct.

http://brulosophy.com/2015/10/12/the-mash-high-vs-low-temperature-exbeeriment-results/

Notice how his OG is the exact same for a 147 vs a 161 mash. It's the FG that WILL differ, which is not efficiency but attenuation.

 

[kh54s10]

Efficiency problems are most often traced to poor milling of the grains. How well are your grains being crushed.

I would not go with a long and low mash to try to fix this, you are trading one problem for another.

 

[Smellyglove]

Can you explain more about how you get better efficiency by mashing at higher temps? I don't think that's correct.

http://brulosophy.com/2015/10/12/the-mash-high-vs-low-temperature-exbeeriment-results/

Notice how his OG is the exact same for a 147 vs a 161 mash. It's the FG that WILL differ, which is not efficiency but attenuation.

Some of the starch granules aren't being dissolved (gelatinized) into water until you reach a specific temperature, like a dextrinization rest, 72C+. But the sugars created at that temp are mostly long-chained ones (tri or beyond), so efficiency goes up and so does FG comparing to if you'd omit that rest. It depends on what you want from your final beer, how to mash it.

However, this is not the "problem" with you hitting 60%. The extra extract you gain from that temp is just a few percent. On it's own those few % would not give you what you seek.

 

[ba-brewer]

Measuring the gravity of the mash to determine complete conversion is what gave me more consistent efficiency. When I just went by time my efficiency would move around quite a bit.

 

[schematix]

Can you explain more about how you get better efficiency by mashing at higher temps? I don't think that's correct.

http://brulosophy.com/2015/10/12/the-mash-high-vs-low-temperature-exbeeriment-results/

Notice how his OG is the exact same for a 147 vs a 161 mash. It's the FG that WILL differ, which is not efficiency but attenuation.

Brulosophy will lead you astray. The guy promotes short and shoddy techniques. But that's another subject.

What you don't know what the gel temp of your grain. He doesn't know either. If it was 140F then yah, you'd see a difference in attenuation just from mash temp. But here you don't know if you have a gel temp of 140F, 145, 150F or even higher. As someone else pointed out, take measurements during your mash. It was *enlightening* when i did. And it's not just a few percent though. It's 10-20% of the maximum, depending upon the grain and the mash schedule. The current stuff i have is nearly 90% converted after 20 minutes at 144. Each step from 144->162->171 yields a little bit more. I don't do it for the extract though, i do it for the body and head retention.

 

[dx250]

What changed my efficiency from 60-80% was milling my own (13% increase) and going from a bazooka screen with manual everything to a false bottom and using a pump for recirculation in the last 10 minutes of the mash. I also added rice hulls to every mash now. My last 2 brews, sub 1.040 og were at or above 90% efficiency. I also have gotten very particular about volumes and hit my preboil dead on most of the time.

 

[Smellyglove]

Measuring the gravity of the mash to determine complete conversion is what gave me more consistent efficiency. When I just went by time my efficiency would move around quite a bit.

If this is correct it sound like you had uneven milling or a general lack of control of your mashing vs the grist that went into the mash tun?

 

[ba-brewer]

If this is correct it sound like you had uneven milling or a general lack of control of your mashing vs the grist that went into the mash tun?

Was mashing in a cooler single infusion, had my own mill and milled to order. I brew many styles of beer, so composition of the grain bill and mash temps varied from brew to brew. I also brew outside. A few drips on the refractometer takes little effort or time.

Even now with a RIMS I still see variation in time to get complete conversion.

 

[Gnomebrewer]

As mentioned already, measure the gravity of your mash when you're done. I'm amazed at how few brewers do this, then try to randomly target why they're getting poor efficiency. Forget about the mash time the recipe says to use - with a normal crush (say, from 0.030 to 0.375") I find the mash is NEVER completed after 60 minutes at mid-range mash temperatures. That may be different for super-fine crush BIAB.
To boost conversion efficiency (and subsequent efficiencies) add in a 72C/162F rest. I find about 15 minutes (after typically an hour at lower temps) is normally enough to get to 100% conversion. Also, mash conversion (not including the sparge conversion) calculators are hard to find - I use this spreadsheet from braukaiser
http://braukaiser.com/documents/efficiency_calculator.xls
Actually, it is far better for all efficiency calculations than Beersmith, which I'm finding has more and more calculation errors.

For a 5 hour mash - as long as there is still beta amylase present, it'll continue to cut up the longer chain sugars and starch into shorter chain (fermentable) sugars, giving a more attenuative wort. If you want to leave things for that long for convenience, raise to at least 162F first after a 30 minute or so rest at a lower temperature.

 

[smata67]

I have gotten 60% efficiency for most of my brewing life (40 or so 6 gallon batches). And that is with grain from various different vendors over the last 10 years. And very consistently at 60%. I used to mash 6 lb of grain for an hour in a bag in a 4 quart pot, usually at 152F, and then added DME to get target OGs. The resulting 3 gallon concentrated wort I would cool and dump into the fermenter and add 3 gallons of water for a 6 gallon batch. Roughly getting half my sugars from grain in this mini-mash.

But I am now going 100% all grain and, looking to increase my efficiency, took this grain to the LHBS and guy there said the crush looked fine. This is a 10 lb MoreBeer bag. This is my second all grain batch, the first one, which is what was in the bucket in the picture, I got 62% (same grain mashed at 152F and finished at 1.013), which prompted my taking the grain to the LHBS to see if they would crush some more. They recommended extending the mash time. The 147F mash temperature, and it may even have started in the low 140s, was accidental, I was shooting for my usual 152F, to see the effect of a longer mash time, but I failed to let the mash settle down right after mixing, been away from brewing for 5 years and forgot to give the grain time to absorb the heat. Thought temperatures were too high and added too much cold water. Anyway, I do see that fiddling with mash temperature or time does not alter the OG or FG (using older BS v1.4), so I conclude, as many have pointed out, that mash temperature or duration does not affect efficiency, though this seems counterintuitive. I guess the longer mash time does not affect the OG, but does the FG due to the improved fermentability? I would guess the OG would be higher due to the longer mash time, but changing the values in BS does not confirm this.

Coming out of the mash tun after 5 hours, 1.047 wort at 120F. And that was 3.75 gallons. Started with 3 gallons of 166F or so water, yielding 1.75 gallons wort and batch sparged with 170F water for 10 minutes with 2 gallons to get 3.75 gallons at start of boil and 3.25 gallons into fermenter.

At one week and 1.003 FG, it actually tastes fine (if a tad boozy) and the mouthfeel is acceptable-- not thin at all, I do have 4oz carapils and 6oz caramel in there. Hop schedule .25oz Magnum for bittering, flavor was .5oz of Pacifica at 30, 20, 10, and 5. IBUs are at 40. Brewers Friend says I have gotten 95% attenuation, 8.4% ABV.

[/ATTACH]

 

[RM-MN]

I got 62% (same grain mashed at 152F and finished at 1.013), which prompted my taking the grain to the LHBS to see if they would crush some more. They recommended extending the mash time.

Conversion does not happen until the starch is gelatinized. That gelatinization and speed of conversion is determined by the temperature and size of particles of the grain. Grains that are crushed finer will have their starches gelatinized quickly and since the particles are so small, they are more completely gelatinized in that short time. As the crush is coarser, it takes more time to gelatinize the starches and eventually, the starches simply do not get all gelatinized as the water does not get to them. That reduces the mash efficiency.

Crushing to flour gets full gelatinization nearly instantly and conversion is complete in less than 2 minutes but....how do you lauter with flour? Increasing the particle size allows you to separate the wort from the grain at the cost of slower conversion and lower mash efficiency.

I guess the longer mash time does not affect the OG, but does the FG due to the improved fermentability?

The longer mash time helps with the OG but with the limitations of the particle size can never reach the OG of a good crush. It also is difficult to keep the mash temperature within the conversion range for a long mash without active heat control but that can cause different problems as adding heat with something like RIMS can cause the enzymes to be denatured as the wort is heated during circulation.