Foam positive temperature rest

[InspectorJon]

I have read several places to do a 10 minute temperature rest at around 162F to improve foam in the final beer. I had intended to do that today, but did not remember until I had already drained the bag. That got me wondering if it was important that the grain still be present for this temperature rest.

Does this rest actually do something to the grain or is it just acting on the sugars and others things that are already suspended in the wort?

What is this higher temperature rest actually doing?

 

[doug293cz]

I don't know what it might do to improve foam, but a rest at temps just below mash-out temps can improve your conversion efficiency if your mash conditions up to that point were insufficient to achieve 100% conversion. The higher temp will speed up gelatinization of any starch that remains, and allow it to be converted into sugars and dextrins, as long as there are amylase enzymes remaining. Some malts can have some portion of starch that is more difficult to gelatinize (higher gelatinization temp) than most of the starch in the malt, and this starch may require more aggressive mash conditions to complete conversion.

Brew on

 

[Miraculix]

I have read several places to do a 10 minute temperature rest at around 162F to improve foam in the final beer. I had intended to do that today, but did not remember until I had already drained the bag. That got me wondering if it was important that the grain still be present for this temperature rest.

Does this rest actually do something to the grain or is it just acting on the sugars and others things that are already suspended in the wort?

What is this higher temperature rest actually doing?

It is mainly about glycoproteins, which form at the elevated temperature. I'm not convinced that the grain must be present, but for the reason @doug293cz just explained, it's certainly a good idea to keep it still in there.

There's another question that might pop into ones head. Which proteins or which type do form these foam enhancing glycoproteins? And would it make sense to elevate the levels of these specific precursors of glycoproteins via a tailored protein rest prior the mash?

In my mind, ten to fifteen minutes in the upper end of the protein rest range might enhance the glycoprotein formation during the higher temperature step at the end. It's also what the Czech are doing and the pilsners I've had over there had amaaaaaaaaaazing foam.

 

[corncob]

I have no explanation, but I have also started doing 10-15 minutes at 162 and the results (efficiency and foam) have been compelling. I will probably not ever remove the step from my routine. I can't swear to it, but there seems to be a mouthfeel or texture improvement as well--a softness or silkiness that is not heavy like you expect from just converting at a higher temp. It really adds a certain something to beers that I mash low for high attenuation.

I do it with an infusion, by the way. Usually go 15 minutes from when I start the underlet.

 

[hottpeper13]

After I pull the bag or finish sparging (3V system) my induction burner takes around 15 min to go from 160* to 175*, so the wort is in the zone and this seems to give very good foam head and lasing. I get complete conversion so not having the grain involved is no big deal.

 

[couchsending]

20 minutes at 160-162 is the jam. Do it on every beer, always.

 

[doug293cz]

20 minutes at 160-162 is the jam. Do it on every beer, always.

Anyone know what the chemical reactions that occur at ~160°F (71°C) and improve head retention are?

"I do it, and it works" testimonials are nice, but I really want to know what makes this work.

Brew on

 

[Bassman2003]

Its part of the famous "Hoch-Kurz" mash. 148F and 162F then on to mashout. This is my basic mash profile for every beer. You can vary the time based upon the mash characteristics you are looking for. A way expanded alternative mash profile would be a 135F dough in, immediate raise to 144F, then to 148F, possible 5 min stop at 152F, then up to 162F finishing with 172F. That is a very foam positive mash schedule.

 

[doug293cz]

Its part of the famous "Hoch-Kurz" mash. 148F and 162F then on to mashout. This is my basic mash profile for every beer. You can vary the time based upon the mash characteristics you are looking for. A way expanded alternative mash profile would be a 135F dough in, immediate raise to 144F, then to 148F, possible 5 min stop at 152F, then up to 162F finishing with 172F. That is a very foam positive mash schedule.

But why is it a foam positive mash schedule? What happens at the higher temp, pre-mash-out rest that aids foam formation/stability?

Brew on

 

[Bassman2003]

I have not read enough Kunze or the others to say exactly why. I know it is documented. Here is a Google AI overview:

Glycoproteins contribute to a positive foam in beer due to their surface-active properties and their ability to interact with CO2 bubbles and other proteins to stabilize the foam. Specifically, the sugar portion of the glycoprotein enhances the hydrophobicity of the protein, allowing it to bind more readily to the surface of the CO2 bubbles. This binding helps prevent the bubbles from collapsing, leading to a more stable and lasting foam.

From Wiki:

Glycoproteins are broken down when mashing during longer rest periods in the range of 50–65°C (i.e. a "protein rest").[7] Conversely, a mash step in the range of 70–74°C increases the extraction of glycoproteins into the wort and they are no longer broken down at this temperature.

More Google AI:

To increase the amount of glycoproteins in your wort, you can adjust your mashing process and potentially consider ingredient choices.
1. Mashing Temperature:

• Mash-out Temperature: A mash step in the range of 70–74°C (158–165°F) is particularly effective for increasing the extraction of glycoproteins into the wort.
• Protein Rest (Avoid or Shorten): Glycoproteins can be broken down during longer protein rests in the range of 50–65°C (122–149°F). Therefore, shortening or avoiding a protein rest can help preserve and potentially increase glycoprotein levels.

2. Ingredient Choices:

• Malt-based Gravity: Ensure a significant portion of your starting gravity (OG) comes from malt (e.g., at least 1.044 or 11°P) as syrups and extracts typically provide more sugar than protein.
• Alternative Malts: Some brewing resources suggest using buckwheat malt, quinoa, or biscuit rice malt to potentially increase head retention, which is related to glycoprotein presence.
• Hops: Brewing hoppy beers is associated with increased head retention.

3. Other Considerations:

• Vorlauf: A 20-30 minute vorlauf in the 165-170°F range can improve overall beer quality and may have some positive impact on foam-positive glycoproteins.
• Boil Technique: A softer boil with limited evaporation (around 6-10% boil-off) is generally recommended for better foam and flavor, and may indirectly impact glycoprotein retention compared to a hard boil.
• Avoid Foam-Negative Ingredients: Some flavorings and spices can be foam-negative, so it's best to avoid them if increased glycoproteins for better head retention are a priority.
• Cold Break: Proper cold break after the boil helps remove trub, which can contain lipids and fats that negatively impact foam, allowing glycoproteins to contribute more effectively.
• Yeast Health: A healthy fermentation contributes to a stable beer, potentially supporting better head retention which glycoproteins are known to enhance.

 

[Broothru]

Its part of the famous "Hoch-Kurz" mash. 148F and 162F then on to mashout. This is my basic mash profile for every beer. You can vary the time based upon the mash characteristics you are looking for. A way expanded alternative mash profile would be a 135F dough in, immediate raise to 144F, then to 148F, possible 5 min stop at 152F, then up to 162F finishing with 172F. That is a very foam positive mash schedule.

What is achieved with the 144F and 152F rests? I, too, do the 148F (beta) and 162F (alpha) rests followed by mash out slightly higher than 172F. Just curious what I might gain with brief rests at 144F & 152F. Also, how long a pause at those temperatures?

 

[Bassman2003]

The 144F rest is for limit dextrinase. The overall time in beta would be split between 144F & 148F. I mash for gravity targets instead of time now, so I can't say an exact time. 152F is something some do that I know. I can't remember to reason, but it was a brief stop like 5 minutes...

For a pale lager or Belgian beer, I stay in beta until 90% of my pre-boil gravity is reached. So I would be at 144F for 20-30 minutes and then the remainder at 148F.

It is interesting to see the list in section 3 of the Google AI on glycoproteins. These are important parts of low oxygen brewing practice as well. Low boil, no trub carry over (mash or boil) and yeast, yeast, yeast. A lot of little bits that add up in the end.

 

[Broothru]

Great info to apply to my mash profiles. I always do step mashes, and adding two more short rests only requires some simple programming of my AIO timer. Making some minor tweaks for the next brew session when we get back home.

Thanks!

 

[Bassman2003]

You are welcome. The 2nd longer mash is often referred to as the "Brauwelt mash". That is a brewing publication in Germany. Yes, with the right equipment, doing one of the famous mash profiles is as easy as a single infusion. This allows the modern brewer to match the mash profile with whatever style or desired fermentability for the beer.

To me, one of the largest changes/improvements I have made in the last few years is moving to letting the gravity readings decide step length instead of time. Every brew system is different so blanket times just do not let the profiles execute as intended. For example, if you crush really fine, your beta conversion will probably a lot quicker than someone who has a coarse crush. Each system needs the proper attention to keep the integrity of the profiles.

A common belief in homebrewing is that beta is denatured and those enzymes are gone in 30 minutes. But the reality is just not that way. If I just did 30 minutes only in beta on my system I would not reach the 90% goal and would always end up with less fermentable wort. When I do go longer in beta the beers have less weight. Not thin but but more towards pro-level attenuation. Its a lever that moves both directions for the brewer to play with.

Once you brew this way a few times, the same repeatability in step length appears and it is predictable.

 

[corncob]

Much truth here. Crush (both average particle size and size distribution) affects conversion (and therefore fermentability) significantly. Often glossed over in homebrew land, in favor of "get your crush repeatable."

Which is good advice, but doesn't tell the whole story.

 

[Bassman2003]

But crush is not a positive or a negative, just a choice that needs to be accounted for.

When we are taught homebrewing, it is all about conversion & gravity points. When you brew long enough, you start to want to "shape" beers. In general, early years of homebrewing produce thick, unattenuated beers. They have a lot of impact and offer a stark difference to say macro lager beers. At first it seems like more flavor, but it is really, being flabby. The tracking of gravity during the mash is the actual work being done for that enzyme.

In my experience, If one wants things like super foam or Belgian/German attenuation, the details need to be learned and followed.

 

[HighVoltageMan!]

There are so many ways to effect foam stability in beer. All the way from grist to fermentation. I have long been a proponent of step mashing, but I really don't have any solid data that it produces a better beer, but it does improve extraction efficiency. I have notice that my beers have improved over the last 5 years or so by routinely mash @ 145F for 90 minutes, 158 for 15 minute and mash out at 168F for 15 minutes. The attenuation on my European lagers (Pils/International lagers, etc.) has crept in the low 80's and yet the mouth feel has improved despite the higher attenuation. This is especially noticeable with Fermentis 34/70. I avoided it because of the thin mouthfeel and low malt character, but it's now one of my favorite yeasts.

The other thing that I have heard and I don't know if it's true, is that pressure fermenting improves mouthfeel and foam. Not sure about that, I guess that's why the Pope of Foam, Dr. Charlie Bamforth, has been researching this for so long, it's really complicated

 

[Bassman2003]

There are so many ways to effect foam stability in beer. All the way from grist to fermentation. I have long been a proponent of step mashing, but I really don't have any solid data that it produces a better beer, but it does improve extraction efficiency. I have notice that my beers have improved over the last 5 years or so by routinely mash @ 145F for 90 minutes, 158 for 15 minute and mash out at 168F for 15 minutes. The attenuation on my European lagers (Pils/International lagers, etc.) has crept in the low 80's and yet the mouth feel has improved despite the higher attenuation. This is especially noticeable with Fermentis 34/70. I avoided it because of the thin mouthfeel and low malt character, but it's now one of my favorite yeasts.

The other thing that I have heard and I don't know if it's true, is that pressure fermenting improves mouthfeel and foam. Not sure about that, I guess that's why the Pope of Foam, Dr. Charlie Bamforth, has been researching this for so long, it's really complicated

"Better" is subjective to what you the brewer wants to achieve. If mashing at 145F for 90 minutes gives you a more fermentable wort resulting in better attenuation, then step mashing is better for you. Have you checked your gravity at the end of your 90 minute rest? It would be useful to know what percentage that number is of your pre-boil gravity.

Your post is an exact example of what I was trying to point out with shaping the beer with the mash profile. BTW, I would say you could stay at 158F for 20min and 168F for only 10 unless you are staying longer at mashout for viscosity reasons.

 

[mac_1103]

In general, early years of homebrewing produce thick, unattenuated beers.

Really? One of my first all grain brews ever was seriously over-attenuated. 85% AA with S-04. Pretty obvious that I mashed too low. Maybe rookie mistakes do tend to group in certain ways, but my own didn't seem to cluster in the thick, unattenuated direction.

Also not sure I completely get what you're saying about tracking gravity during a step mash. That will tell you how much starch you've gelatinized and converted to something soluble. It won't tell you the molecular weight distribution of that soluble sugar, which is what determines fermentibility, right? Seems to me that gravity is going to keep increasing with time, even if your thermometer is out of calibration.

 

[Bassman2003]

Sorry, I over generalized to prove a point that early on we don't have the knowledge to know to get attenuation into the 80's. Evidenced by the yeast companies often saying their yeast get in the mid 70's. It's a mid-target and is fine unless one wants more.

Well gravity at a certain rest is the concept. Do you want your sugars extracted from beta or alpha? Yes, if you stay in beta for 5 hours (famous Bud Light mash schedule) you will get to a desired sugar level. But is that the type of beer you are looking for?

 

[HighVoltageMan!]

"Better" is subjective to what you the brewer want to achieve.

I started winning at NHC finals. So yeah, I would say my beers improved. But I made several changes, including pressure fermenting, so I can't say objectively that step mashing did it or whatever. All I can point to a that it may be a combination of things. That's why it's difficult to say step mashing is the way to go.

If mashing at 145F for 90 minutes gives you a more fermentable wort resulting in better attenuation, then step mashing is better for you. Have you checked your gravity at the end of your 90 minute rest?

The gravity will plateau at some point in the first rest, each step afterward will increase the gravity slightly. The overall extraction rate in the mash is @ 90%, sometimes a little higher or lower. I believe that step mashing or any other technique is system dependent. Just because it works for me doesn't mean it will work for someone else with a different system (I have a RIMS system with a constant vorlauf). What I found to be surprising is despite the really good attenuation, the mouth feel and head retention is much better even with 34/70 yeast.

BTW, I would say you could stay at 158F for 20min and 168F for only 10 unless you are staying longer at mashout for viscosity reasons.

I don't how it could hurt anything, I often wonder if the rest at 158 is the most beneficial after the the sach rest, but I am seeing a bump in gravity at the 168F rest.