End results with low mash efficiency

[ninkwood]

I completed my 3rd all grain mash yesterday - an attempt at a German wheat beer.

My grain bill was:

60% wheat malt
35% pilsner Malt
5% carapils

This brew did not go well after nailing my ph adjustment ~10 min into the mash. I ended up with approximately 55% mash efficiency.

After completing extensive research last night, I'm 99% sure that the issue with mash efficiency was the grind on my wheat malt. I do not have my own mill and am relying on obk which sends me 1lb premilled bags of grain from mash king. I think I can sort this out going forward by buying a grain mill, but my concern right now is for the quality of this latest batch.

I adjusted the recipe on the fly by decreasing the batch size by skipping my 1 gallon fermenter top up. This left me with a OG of 1.044 instead of 1.051, but also a smaller volume in the fermenter as well.

So obviously the ABV is going to be lower (around 4.2% instead of 4.9%). And I assume the beer will also have higher than desired bitterness (though I did attempt to correct for this by reducing the amount of hops). Will the resulting beer still have a chance at being "good", or will other parameters be way off here? Specifically, I'm wondering if the mash efficiency is correlated with flavor/colour extraction? So even if my ABV and bitterness are close, I could still end up with a much darker/maltier tasting beer than desired.

Does anyone have experience with how really low mash efficiency impacts the end product?

 

[lumpher]

Don't worry about it tasting bad or off because of low efficiency. It sounds like from the corrections you made you should come out close enough to the same beer, just a little less of it. Besides, if it's just for daily drinking instead of some contest, Hefe's are very forgiving for any errors.

 

[Red over White]

As you stated above, you will be really, really close to your recipe, but the color might be slightly different in the glass. I don't think you will be able to taste a difference, with the subtle changes you had. I'm sure if you do get your own mill and check your gravity as you mash you will be really consistent with the volume and gravity going into the kettle.

I don't use software for recipes, I do it all by hand because I really enjoy that part. When mashing I use braukaisers first wort chart to guide how long I mash, so I hit my numbers. It is helpful to check as I go and mash longer if need be. For no sparge it's really simple to use his chart.

lbs grain x qt/lb ÷ 4 = gals strike @ °Plato

22x2.54÷4=14 gals @12.7 °P or ~1.051
This will give me 12 gals (measured hot including expansion) preboil at 1.051 in the kettle.

 

[ninkwood]

Really glad to hear from both of you that you don't think the low mash efficiency will make this batch a dumper on its own!

At the least, I want to make sure I'm learning from these first batches, and in this particular part of the brew I think I regressed a bit. In my second batch, I was watching the gravity closely and ended up mashing an hr and a half, then actually overshot pre-boil target by a couple points. But on this more recent batch I took my expected efficiency for granted. So in a round about way, lesson learned there! Good to know that if the beer doesn't turn out, then I shouldn't just blame it on my low efficiency.

I don't use software for recipes, I do it all by hand because I really enjoy that part. When mashing I use braukaisers first wort chart to guide how long I mash, so I hit my numbers. It is helpful to check as I go and mash longer if need be. For no sparge it's really simple to use his chart.

View attachment 840897

lbs grain x qt/lb ÷ 4 = gals strike @ °Plato

22x2.54÷4=14 gals @12.7 °P or ~1.051
This will give me 12 gals (measured hot including expansion) preboil at 1.051 in the kettle.

I'll be honest, I'm not really following this part. What I've been doing is using brew father to adjust a recipe for my BIAB setup as best as I can. I mash in then wrap my mash tun/kettle in a few winter coats. I check ph around 10 min and adjust if necessary then take a gravity about 10 min after that. In this latest batch my gravity was super low after 20 min but I blamed that on the high pH and when I checked again around 40 min it had increased by a large enough margin I assumed I was fine to just end it at 60 min but not so. It increased, but not nearly enough.

I'll either get myself a grinder before my next batch of wheat beer, order double ground grains, or just simply mash as long as I need to to hit a more acceptable efficiency. Depending how much effort this is will dictate how quickly I buy the mill!

Thanks to you both!

 

[pvtpublic]

With that much wheat, do you use rice hulls? If not, that could be part of the problem. The hulls on barley act as a filtering medium, allowing the wort to flow through all of the grain particles easier. Wheat doesn't have a hull on it, and tends to be gummier than barley, often making run-off a bit tricky. Even if you have a good flow out of the mash tun, you might still be getting some channeling inside the grain bed, which could explain the poor efficiency.

Another thing to ask, how fast are you lautering? Going too fast could create a vacuum and compact the grain bed, also leading to channeling, especially with that much wheat.

 

[doug293cz]

With that much wheat, do you use rice hulls? If not, that could be part of the problem. The hulls on barley act as a filtering medium, allowing the wort to flow through all of the grain particles easier. Wheat doesn't have a hull on it, and tends to be gummier than barley, often making run-off a bit tricky. Even if you have a good flow out of the mash tun, you might still be getting some channeling inside the grain bed, which could explain the poor efficiency.

Another thing to ask, how fast are you lautering? Going too fast could create a vacuum and compact the grain bed, also leading to channeling, especially with that much wheat.

OP stated that they BIAB (What I've been doing is using brew father to adjust a recipe for my BIAB setup as best as I can.), so probably not sparging at all. So, channeling makes zero difference. Channeling is also not an issue if batch sparging; it only comes into play when fly sparging.

Brew on

 

[waynetempro]

You do need to change the gap in the grain mill for wheat. It is a smaller grain and will not crush correctly at the normal barley settings. Don’t forget to reset the mill after you are done.
Also based on your recipe, you will need about a pound of rice hulls to avoid a stuck mash.

 

[ninkwood]

My current mash technique for BIAB (which I'm certainly open to adjusting) has me resting with lid on and insulated behind some winter jackets. I usually stir/adjust ph/take gravity every 10-15 min for 1 hour. Going forward though (until I buy a mill) I'll keep mashing until I hit my number, and might not do another wheat beer until I buy said mill. I can also use flaked wheat in my future neipas that I have planned as that will help with this issue too.

I also do a boil top up as I'm brewing in a 6 gal kettle and prefer to get to 4.25 gal of beer out of the fermenter. Ive been heating this top up water to around 170*f and washing the grain bag as it drains into the pot. This might help explain where I'm coming from better.

Seems like the issue in this case was a combination of poor grind and impatience on my part. I can fix the latter on my next batch and I think I'll also use a lower efficiency number as a further safeguard until I buy the mill!

Thanks gents!

 

[Red over White]

On paper you had the diastatic power to convert, if you hit gelatinization temperature. If you didn't hit gel temperature and the crush was good, time was your friend.

Very rarely have I seen malt just not have the enzymes to convert. Whether it was malt age, terrible storage or bad malting, I've only experienced it just twice, in 30 years.

 

[ninkwood]

On paper you had the diastatic power to convert, if you hit gelatinization temperature. If you didn't hit gel temperature and the crush was good, time was your friend.

Very rarely have I seen malt just not have the enzymes to convert. Whether it was malt age, terrible storage or bad malting, I've only experienced it just twice, in 30 years.

Yup, same conclusion I've come to - I was aware of the diastaic power ahead of time and to be cognizant of that when setting up brews, but I had not heard about the challenges with gelatinizing wheat, or the challenges with grinding it.

Good lessons for me on this batch as I'm realizing my BIAB efficiency will likely be significantly better after buying a mill. I'm just focusing on other purchases first

 

[doug293cz]

I also do a boil top up as I'm brewing in a 6 gal kettle and prefer to get to 4.25 gal of beer out of the fermenter. Ive been heating this top up water to around 170*f and washing the grain bag as it drains into the pot. This might help explain where I'm coming from better.

Your "washing the grain bag" is a form of sparging (rinsing the spent grains) that is somewhat similar to fly sparging. As such it is prone to channeling, which reduces the efficiency of the sparge. The main problem with a pour over sparge is that it is probably the least repeatable form of sparge, and this makes predicting the outcome of your mash and lauter less reliable.

You might want to consider switching to a dunk sparge. All you need (in addition to what you already have) is a 5 gallon plastic bucket. Then after draining the initial mash, squeezing the bag if you are into that (it will improve your efficiency), drop the bag of grain into the bucket, add your sparge water, stir well, and then drain and optionally squeeze. The advantage of a dunk sparge is that it is much more consistent than a pour over sparge. A good rule of thumb when dunk sparging is to use 60% +/- of the total water required for mashing, and the balance for sparging.

And, with either form of sparging, you don't actually have to heat the sparge water, although that will shorten your time to heat to boil.

Brew on

 

[ninkwood]

Your "washing the grain bag" is a form of sparging (rinsing the spent grains) that is somewhat similar to fly sparging. As such it is prone to channeling, which reduces the efficiency of the sparge. The main problem with a pour over sparge is that it is probably the least repeatable form of sparge, and this makes predicting the outcome of your mash and lauter less reliable.

You might want to consider switching to a dunk sparge. All you need (in addition to what you already have) is a 5 gallon plastic bucket. Then after draining the initial mash, squeezing the bag if you are into that (it will improve your efficiency), drop the bag of grain into the bucket, add your sparge water, stir well, and then drain and optionally squeeze. The advantage of a dunk sparge is that it is much more consistent than a pour over sparge. A good rule of thumb when dunk sparging is to use 60% +/- of the total water required for mashing, and the balance for sparging.

And, with either form of sparging, you don't actually have to heat the sparge water, although that will shorten your time to heat to boil.

Brew on

Appreciate this advice!

I actually have a second 5 gallon stock pot that I use to hold the grain bag after done the "squeeze". I never thought to do the pour over in this second pot and do a "dunk sparge" but I'll definitely give this a go!

At this stage, I'd rather over shoot my gravity than make a perfect beer. I'm more focused on efficiency and consistency than beer quality. I also am doing more like 75/25 split. I figure maximizing the amount of water in the mash will give me the best possible efficiency. But again I'll give your recommendation a go on my next batch.

Another question in relation to this topic. If I did a dunk sparge, then topped up the boil with most of this water, would it be feasible to top of the fermenter with unboiled wort? I've been afraid to do this for sanitary reasons, but also because I know at least a 30 minute boil is important. I suppose i could do two side by side boils, but brew days are complicated enough.

 

[VikeMan]

I also am doing more like 75/25 split. I figure maximizing the amount of water in the mash will give me the best possible efficiency.

If maximizing the amount of water in the mash (i.e. in the strike volume) gave the best efficiency, then a no-sparge would give better efficiency than a batch spage, and that's not the case.

The highest lauter efficiency with a batch sparge will be when your first and second runnings are equal. (Not the actual infusion volumes, but the runnings.) Assuming no dead spaces or transfer losses, you could compute the ideal volumes as follows:

Strike Volume = (1/2 x preboil volume) + grain absorption
Sparge Volume = 1/2 x preboil volume

 

[doug293cz]

Appreciate this advice!

I actually have a second 5 gallon stock pot that I use to hold the grain bag after done the "squeeze". I never thought to do the pour over in this second pot and do a "dunk sparge" but I'll definitely give this a go!

At this stage, I'd rather over shoot my gravity than make a perfect beer. I'm more focused on efficiency and consistency than beer quality. I also am doing more like 75/25 split. I figure maximizing the amount of water in the mash will give me the best possible efficiency. But again I'll give your recommendation a go on my next batch.

Another question in relation to this topic. If I did a dunk sparge, then topped up the boil with most of this water, would it be feasible to top of the fermenter with unboiled wort? I've been afraid to do this for sanitary reasons, but also because I know at least a 30 minute boil is important. I suppose i could do two side by side boils, but brew days are complicated enough.

Lauter efficiency is maximized for a single batch/dunk sparge when the volumes of the initial draining and sparge draining are equal. You need more water in the mash, since the grain will hold some of the wort volume. Grain absorption doesn't affect the sparge because the grain starts out with as much liquid as it can hold after draining. A 60:40 volume split gives you pretty close to equal drained volume when you take grain absorption of the mash water into account.

I would never top up a fermenter with un-boiled wort. There are bacteria that can survive mash temps (IIRC Lactobacillus is one, and it can sour your beer), so I recommend boiling at least 5 - 10 minutes any wort that you want to use to top up the fermenter.

Brew on