Adding Amylase Enzyme After a Stalled Fermentation

[BitterSweetBrews]

I have a 5.5 gallon batch of an American stout with an OG that started at 1.064 (the exact BeerSmith estimate). It has stalled at 1.030. The expected final gravity from BeerSmith is 1.016.

I mashed at about 155-156f. During the mash out I realized that I didn't mash the flaked oats, I lowered the temp to 153 and added them and some additional quick oats in for an additional 45 minutes. I also added a tsp of amylase enzyme. I don't thing there was much enzyme in the mash at that point to break the oats down but I though it worth a shot.

I used Voss Kviek. I started fermenting at room temp and raised the temp to about 82-83f degrees after a day.

It has been fermenting for over 2 weeks and has sat at 1.030 for a week.

The expected ABV was 6.4. It is now sitting at 4.5%. Not a huge difference, but I think it would taste a bit better if it was a little less sweet.

I have shaken and swirled the fermenter a couple times to attempt a jump start but it hasn't done any good.

So, yesterday I added the Carlson bottle recommendation of 1/2 tsp Amylase enzyme for 5 gallons. I swirled the fermenter again. Today the gravity is still at 1.030.

My question is how long do you think it will be before I see any effect from the enzyme breakdown?

I am patient and have plenty of beer, so I can wait as long as it takes. Just curious if anyone else done this and had good results.

Thanks
Tim Trabold

 

[Vale71]

I have a 5.5 gallon batch of an American stout with an OG that started at 1.064 (the exact BeerSmith estimate). It has stalled at 1.030. The expected final gravity from BeerSmith is 1.016.

I mashed at about 155-156f. During the mash out I realized that I didn't mash the flaked oats, I lowered the temp to 153 and added them and some additional quick oats in for an additional 45 minutes. I also added a tsp of amylase enzyme. I don't thing there was much enzyme in the mash at that point to break the oats down but I though it worth a shot.

I used Voss Kviek. I started fermenting at room temp and raised the temp to about 82-83f degrees after a day.

It has been fermenting for over 2 weeks and has sat at 1.030 for a week.

The expected ABV was 6.4. It is now sitting at 4.5%. Not a huge difference, but I think it would taste a bit better if it was a little less sweet.

I have shaken and swirled the fermenter a couple times to attempt a jump start but it hasn't done any good.

So, yesterday I added the Carlson bottle recommendation of 1/2 tsp Amylase enzyme for 5 gallons. I swirled the fermenter again. Today the gravity is still at 1.030.

My question is how long do you think it will be before I see any effect from the enzyme breakdown?

I am patient and have plenty of beer, so I can wait as long as it takes. Just curious if anyone else done this and had good results.

Thanks
Tim Trabold

You won't "see" any effect from the enzyme as all the enzyme does is create more fermentable sugars but will not in any way restart the fermentation. You might be able to taste the difference as fermentable sugars taste much sweeter than dextrins. To restart the fermentation you need to actually adress the reason why the fermentation stalled in the first place.

 

[BitterSweetBrews]

You won't "see" any effect from the enzyme as all the enzyme does is create more fermentable sugars but will not in any way restart the fermentation. You might be able to taste the difference as fermentable sugars taste much sweeter than dextrins. To restart the fermentation you need to actually adress the reason why the fermentation stalled in the first place.

If it is creating fermentable sugars why wouldn't the fermentation "re-start" and the existing yeast eat them up? That's the whole point of adding the enzyme. I realize that I'm not going to magically see a 1" kreusan, but as these new short, more fermentable molecule chains are present in the wort the existing yeast should start to work on them. It isn't that much different then adding priming sugar. Once the yeast sees suger in the wort that it can eat, it does.

I have read a number of posts where people have added enzymes and the gravity reduces considerably.

 

[Rob2010SS]

You've already added the enzyme. I'd give it a couple of days and check again. If still 1.030, I might try and add a small yeast starter at high krausen and see if that helps. I've had luck once with adding a starter at high krausen to kick start a stalled fermentation and drop it a little bit more. Outside of that, not sure what you could do.

***EDIT*** By no means do I KNOW that this will work. I get what the amylase enzyme is doing but I have no idea how long it takes as I've never used it. What I said above is quite frankly just something I would try to see if it helps.

 

[BitterSweetBrews]

You've already added the enzyme. I'd give it a couple of days and check again. If still 1.030, I might try and add a small yeast starter at high krausen and see if that helps. I've had luck once with adding a starter at high krausen to kick start a stalled fermentation and drop it a little bit more. Outside of that, not sure what you could do.

***EDIT*** By no means do I KNOW that this will work. I get what the amylase enzyme is doing but I have no idea how long it takes as I've never used it. What I said above is quite frankly just something I would try to see if it helps.

Great advice about the starter, I might try that. I have read that elsewhere.

I have read people say that they had added "Beano" and it worked in a week or so but to stay away from it. From what I understand, the Beano enzymes are not the same ones as in the Amylase Enzyme brewing enzymes. These are Alpha Amylase enzymes that will break down the longer chain starch molecules into short chain dextrins which will ferment. I have read that they do eventually stop, unlike the enzymes in Beano which eat everything in site.

As I said, I am in no hurry and plan on leaving it for a while to see what happens. I hope it is positive. The beer currently tastes pretty good, but just needs a little bit more warmth and little less sweet. Next time, I may mash about 4 degrees cooler, more towards the center of the brewers window.

 

[Vale71]

If it is creating fermentable sugars why wouldn't the fermentation "re-start" and the existing yeast eat them up? That's the whole point of adding the enzyme. I realize that I'm not going to magically see a 1" kreusan, but as these new short, more fermentable molecule chains are present in the wort the existing yeast should start to work on them. It isn't that much different then adding priming sugar. Once the yeast sees suger in the wort that it can eat, it does.

I have read a number of posts where people have added enzymes and the gravity reduces considerably.

Yes, unfortunately people post a lot of stuff that then gets repeated without necessarily understanding what is exactly happening.

So you say you have a stalled (i.e. incomplete) fermentation. This means that the beer is not at FG, there are still fermentable sugars available but the yeast has quit its job for one of several possible reasons or a combination of reasons.

Why should the solution be "Let's add some enzyme to create even more fermentable sugars that the yeast then won't ferment as it has quit doing its job?" instead of "Let's fix the issue(s) and see if fermentation restarts and the beer gets to FG?" This simply makes no sense, it's like putting more gasoline in a car with a totalled engine hoping that this will fix the engine.

 

[BitterSweetBrews]

Yes, unfortunately people post a lot of stuff that then gets repeated without necessarily understanding what is exactly happening.

Actually, I think that I do understand exactly what is/was happening. Fermentation has stopped because there are no more fermentables available for the yeast to eat, for whatever reason. I suspect that it is because I fermented it on the high end of the brewers window, where the Alpha Amylase works pretty hard randomly breaking down the starch chains and not releasing many maltose molecules (M.A.L.T. More Alcohol Lower Temp). This leaves many more unfermentable, odd length ones with the maltose still trapped. If I had mashed a few degrees cooler at a more balanced temp, I am sure we wouldn't be having this discussion. Adding the additional amylase gives it a second chance to eek out some more maltose molecules from those odd length chains .

So you say you have a stalled (i.e. incomplete) fermentation. This means that the beer is not at FG, there are still fermentable sugars available but the yeast has quit its job for one of several possible reasons or a combination of reasons.

I don't think the fermentation stalled. I think it stopped.

I don't know if you caught everything in the initial post, but, I used Voss Kveik. I obtained this as slurry from a brewery that uses it to make some great beers. It is purported to be such a powerful Kveik (yeast) that it thrives in bad situations. It can be underpitched with great success (I didn't under pitch, as I made a starter, which was probably unnecessary). Voss Kviek works great at high temperatures I would never subject another yeast strain too (I would have liked to ferment at 85 or higher but could only get it to 83f with my heating pad. Voss gives off some pretty great fruity esters, while avoiding the fusels of other strains. In addition to to all this ,it is a monster fermenter. It is fast like a pacman, sometimes finishing in just 3-4 days.

Why should the solution be "Let's add some enzyme to create even more fermentable sugars that the yeast then won't ferment as it has quit doing its job?"

Why not? I don't understand why you think the yeast would refuse to ferment these additional sugars created by the additional starch breakdown. Maltose is maltose. The yeast doesn't just die. If that happened then don't ever try pouring a new batch on the last batches yeast cake or try to harvest yeast.

instead of "Let's fix the issue(s) and see if fermentation restarts and the beer gets to FG?" This simply makes no sense, it's like putting more gasoline in a car with a totalled engine hoping that this will fix the engine.

Pouring more gas in a car is a great solution, if you ran out of gas. Which is exactly what I think has happened. The engine (wort) isn't totaled, just starved of fuel. It needs more fuel and a jump start.

One of my cars is in the shop getting a replacement transmission right now. I came real close to totaling it, but the engine is good, so I put a used trans in it. I didn't go for an all new or rebuilt one because it wasn't worth it for that vehicle. I did what was necessary to make it usable.

In this case, if this doesn't do any good I will still have a usable, pretty good beer.

Other than re-pitching more yeast (which per the above I deemed not worthwhile) I think Amylase is the next best, low negatives, last chance solution, given that I have tried to rouse the yeast multiple times. It is also a good experiment with something I have never tried before.

If it works, great, if it doesn't, that's not a problem. Nothing ventured, nothing gained. I plan on giving it a couple of weeks to play out. In the end I'll still keg it, carbonate it and drink it just at well. It is pretty tasty and I bet will grade pretty well. I am just striving for something just a little better.

Cheers.
Tim Trabold

 

[Vale71]

Sorry, but since you mentioned a "stalled fermentation" in the thread title I assumed this was what you actually meant.

BTW, there's no way your fermentation is done at just 54% apparent attenuation, no matter how high you mashed. Unless you actually lost control of your mash temp and prematurely destroyed the enzymes, which would then mean that you'd have a lot of unconverted starch in your beer. Fotunately, a simple iodine test can tell you if this is the case.

Even the most powerful yeast can have issues and stall prematurely for a number of reasons. This happens more often than you might think, especially with homebrewers.

 

[ebbelwoi]

How much oats did you add? Was it about enough to account for the difference between your current gravity and your target FG?

Also, did you add any yeast nutrient? I keep reading that Voss likes nutrient (I always use it), but maybe 1.064 is big enough that nutrient isn't necessary?

Maybe try pitching another yeast (not champagne yeast though) or starter?

Just spitballing here.

 

[BitterSweetBrews]

Sorry, but since you mentioned a "stalled fermentation" in the thread title I assumed this was what you actually meant.

I guess this is just semantics. At this point, having changed temps and rousing the yeast I think it is stopped (or stalled). Whatever the word, stalled or stopped doesn't really matter, it still is hung.

BTW, there's no way your fermentation is done at just 54% apparent attenuation, no matter how high you mashed. Unless you actually lost control of your mash temp and prematurely destroyed the enzymes, which would then mean that you'd have a lot of unconverted starch in your beer. Fotunately, a simple iodine test can tell you if this is the case.

Yeah, 54% attenuation sucks and it wasn't even that high of a gravity.

I don't think that I lost control of the mash. I had the PID at 155 and recirculated the whole time. I calibrated the sensor with the strike water at 154 as it was coming up to temp with a couple other digital thermometers (I never completely trust the sensor in the kettle and calibrate every brew). I checked it periodically during the mash with other thermometers and with another PT100 sensor in the mash on another PID during mashing

I actually did an Iodine test after the initial mash and after the subsequent extended mash after adding in the oats I forgot. It had fully converted both times.

Even the most powerful yeast can have issues and stall prematurely for a number of reasons. This happens more often than you might think, especially with homebrewers.

Agreed, it happens. I tested the SG last night, two days after the added enzymes and it hasn't changed. I think I am going to give it until Sunday (3 more days) and if it doesn't change I will lower the temp in the fermentation chamber, add another starter of a different yeast (maybe some Rogue Pacman) or throw in a pack of S-04. I had hoped to harvest the Voss, but I do have another vial I can get more from. Or, I guess I could transfer it to a secondary and make a starter from the existing yeast cake. I had considered Oaking it. Lots of options.

 

[BitterSweetBrews]

How much oats did you add? Was it about enough to account for the difference between your current gravity and your target FG?

Also, did you add any yeast nutrient? I keep reading that Voss likes nutrient (I always use it), but maybe 1.064 is big enough that nutrient isn't necessary?

Maybe try pitching another yeast (not champagne yeast though) or starter?

Just spitballing here.

Thanks for the comments.

In total, I think I added 1 pound of oats. 12 ounces flaked oats from the LHBS and 4 ounces of quick oats. I did add some yeast nutrient in the starter and more into the fermenter when it first appeared stalled.

I am leaning towards pitching more yeast in a few days if the amylase doesn't do anything (it hasn't appeared to do anything yet). I have a good harvested yeast selection and could build something up or throw in a pack of something. I have 3 or 4 dry yeasts - s-04, s-33, us05. Windsor, ManJacks West Coast and a couple different champagnes (LOL).

 

[Althozgraz]

I think i may have some answers. I brew with kveik almost exclusively at this point using the gjernes, framgarden, hornindal, hothead, and a Lithuanian yeast. some I got from friends in Scandinavia and others i got from yeast labs. Kveik is weird in other ways than just its fermentation temp and flavor profile, its also temperamental in ways you wouldn't think. 1 all kveiks are nutrient intensive so use yeast nutrient sometimes I use twice as much as i normally would. 2 what your yeast has done prior to pitch is very important as well as what kind of beer you are making (OG etc). my process is I take dried yeast I dried myself out of the freezer on brew day and re-hydrate using 200 ml I pull off the wort after sparge is complete, cool and pitch. By the time my boil is done the kveik is usually vigorously fermenting the wort I pitched it in to re hydrate. I then pitch in the mid 90s and within 2-4 hours my beer is fermenting. I do this because a vitality starter like what I did is what these strains are used to and helps avoid your situation of a stalled ferment which is common with kveik but avoidable. In the future try pitching dried yeast you harvested from a batch, for some reason kveik always ferments better for me when it was dried compared to pitching a pack of wet yeast I bought. Also kveik doesn't like being over pitched, it makes it lazy and prone to stalled ferments, seriously almost no amount of under pitching seems to phase this stuff. If you do have a stuck fermentation I recommend making a new yeast starter and waiting until its very active then pitching that, it should restart you fermentation. It shouldn't take much even 100 ml of starter has worked for me in the past.

 

[Pokey46]

Hi Jim, I'm curious to hear how this turned out, if you don't mind providing an update.

3 of my last 4 batches failed to ferment quite as low as I expected, all different recipes with different yeasts, most of which I'm very familiar with. The latest Oatmeal Stout fell short the most - stopping around 1.021 instead of the planned 1.015, using Wyeast 1084. I eventually concluded that I was likely mashing a bit too warm and doing a batch sparge way too warm. Ferm wasn't stopped for long - only a couple of days, but I use a Tilt and tiltpi to stream readings to brewersfriend so get good fermentation graphs of all of my brews, and was confident I was seeing a repeat of the pattern that occurred on the 2 earlier brews which never did ferment as dry as expected. Anyhow, after reading some other threads I decided for this batch to try adding 1/4 tsp of amylase enzyme in the primary - for as much as any other reason to test my theory about temps and fermentability of the wort. It seems to have worked very quickly - 9 hours after adding that enzyme, the gravity was starting to drop and the airlock activity is steady - 23 hours now after adding the enzyme the gravity is 1.015. I'm hoping it doesn't go too much lower, but in any case I'm learning a few things...

Cheers,
Richard

 

[Rfox2014]

Hi Jim, I'm curious to hear how this turned out, if you don't mind providing an update.

3 of my last 4 batches failed to ferment quite as low as I expected, all different recipes with different yeasts, most of which I'm very familiar with. The latest Oatmeal Stout fell short the most - stopping around 1.021 instead of the planned 1.015, using Wyeast 1084. I eventually concluded that I was likely mashing a bit too warm and doing a batch sparge way too warm. Ferm wasn't stopped for long - only a couple of days, but I use a Tilt and tiltpi to stream readings to brewersfriend so get good fermentation graphs of all of my brews, and was confident I was seeing a repeat of the pattern that occurred on the 2 earlier brews which never did ferment as dry as expected. Anyhow, after reading some other threads I decided for this batch to try adding 1/4 tsp of amylase enzyme in the primary - for as much as any other reason to test my theory about temps and fermentability of the wort. It seems to have worked very quickly - 9 hours after adding that enzyme, the gravity was starting to drop and the airlock activity is steady - 23 hours now after adding the enzyme the gravity is 1.015. I'm hoping it doesn't go too much lower, but in any case I'm learning a few things...

Cheers,
Richard

How low did your gravity get after adding amylase enzyme? I have some sitting around and have an IPA that is potentially going to end high. Doing some research on this.

 

[passedpawn]

How low did your gravity get after adding amylase enzyme?

amylase should take your beer to ~85% attenuation. That's the limit for barley wort and amylase. The other 15% are large sugar molecules that amylase doesn't cleave apart, and thus the yeast can't use.
So, for example, if your beer started out at OG = 1.060, and you added amylase and waited, you'd end up with 60 * 0.15 = 1.009. That might be too low for many beers.

When we brew, we control the speed of the enzymatic action with mash temperature, and then destroy (denature) the enzymes in the boil. Since our mash sessions typically are about an hour, the enzymes aren't finished and we are left with more unfermentable sugars in the wort, resulting in higher final gravity. Adding enzymes to the fermentor and waiting for 2-3 weeks will get you to the limit of attenuation.

[edit] I had that 85% number stuck in my head for a long time, but I just looked up some research done by Kai Troester and it seems to indicate it could be higher. Search Kai Troester Limit of Attenuation and see for yourself.