Efficiency trouble for high gravity beers

[Mike]

My system has an efficiency around 67%. I normally hit my OGs regular (1.060 and lower) beers. I've made a few big beers and have come up at least 10 points short of my expected OG. Using the breakfast stout I made last weekend as an example, I was expecting an OG of 1.085 and got 1.075. It's just weird to me that I hit my OGs on normal beers, but come up short on big beers. It almost makes me think that the mash liquid can only take so much sugar.

Thoughts?

 

[Malkore]

how much water are you using in the mash, water to grain ratio?

you may need to adjust up or down...here's the basic thoughts behind it:

a thicker mash (less water) means the enzymes stay in closer contact with the grains, and thus give better conversion...
a thinner mash thins the enzymes out, but you you get more rinsing of sugars.

a possible thought is that you could try a thicker mash, and then a bigger sparge, and include a mashout. if you batch sparge you could even do two sparges to make that larger sparge volume of water easier to deal with. I've done this myself...done two sparges with 2.25gallons of water per running, instead of a single 4.5gallon sparge.

other thoughts (again I only batch sparge)...stirring the mash up enough before draining? vorlaufing enough?

 

[Mike]

I normally do grist ratio of 1.3 qts/lb. Palmer suggests anything between 1.0-1.5. I was given a batch sparge spreadsheet years ago that gives you water volumes, temps, etc. and I used my programming skills to create a program out of it.

The spreadsheet originally called for a small mash out, but I decided to just have two infusions ("Initial" = strike and "Final" = sparge in the screenshot). I've done two sparges once before when the amount of sparge water was too much to pick up.

I stir up grist before I drain the mash and sparge. I vorlauf probably a gallon or two before I drain each as well.

 

[smurfe]

Combo of mash thickness, the quality of the crush with the grain, the sparging method, equipment set up and most important which most overlook or are not aware of, you water mineral profile. I would say the problem is with the crush and water pH. If you know your water profile you can make adjustments and see a tremendous boost in efficiency. Basically you need to dial in your system and know your water. If you can average 75%, you are doing great, don't get hung up in numbers. I have found I was getting 90% + on my system. The beers were not as good as beer where I stayed right at 80%. One final tip. ALWAYS keep DME on hand to add to boost your OG.

 

[smurfe]

BTW, what do you mash in?

 

[Mike]

I have a barley crusher and have the gap set at 0.032". I had been doing mineral additions based on an online calculator, but for the past couple batches, I've just thrown a tbsp of gypsum into the mash, sparge, and boil. I mash in a converted cooler.

 

[TheTooth]

My system has an efficiency around 67%. I normally hit my OGs regular (1.060 and lower) beers. I've made a few big beers and have come up at least 10 points short of my expected OG.

Hi Mike,

This is a fairly normal phenomenon. You will simply get lower efficiency with big beers. The only way you can offset this by doing bigger sparges and boiling for hours to concentrate the wort back down to hit your gravity. In a few cases (some barley wines, for instance) this is preferential to create more melenoidens, but in general you should just expect your efficiency to be lower than when you make a normal beer.

 

[Mike]

Why doesn't Promash take this into account?

I suppose then that I need to get my refractometer busy preboil. Is there a calculator/equation that will tell you what your OG will be based off a preboil SG using boil time (and perhaps kettle diameter as an input? Is boiling longer the only viable option or can I just add DME? Would adding DME correct the OG, but reduce the effect of specialty grains?

 

[TheTooth]

Why doesn't Promash take this into account?

I suppose then that I need to get my refractometer busy preboil. Is there a calculator/equation that will tell you what your OG will be based off a preboil SG using boil time (and perhaps kettle diameter as an input? Is boiling longer the only viable option or can I just add DME? Would adding DME correct the OG, but reduce the effect of specialty grains?

ProMash can't really take this into account because it doesn't know what your efficiency will be. It will account for the boil if you extend it.

A longer boil isn't the only way. It's just one way. You can also add DME. A DME addition to help reach the desired OG is a very typical practice. Additionally, you can punch in a lower efficiency into ProMash and add grain/fermentables until you get what you want. This is what I do... but there is nothing wrong with the other two methods.

Adding DME won't necessarily affect the effect of specialty grains. Adding DME is really like adding more base malt (2-row, pale, pilsner, etc...) to your grist. In other words, it won't take away any color and it won't dilute the flavor from your specialty grains. It will change things slightly percentage-wise, but the effects will be negligible in my opinion.

 

[Mike]

What do you mean Promash doesn't know what your efficiency will be? It's a value you enter. Whether the equation to determine decreased efficiency as gravity increases is logarithmic or whatever, there has to be a way to calculate it.

 

[TheTooth]

What do you mean Promash doesn't know what your efficiency will be? It's a value you enter. Whether the equation to determine decreased efficiency as gravity increases is logarithmic or whatever, there has to be a way to calculate it.

If you give your efficiency on a low-gravity beer, there might be a way to calculate the lower efficiency of a high-gravity beer... but it would be tough. The way ProMash is set up, it assumes you know what your efficiency will be with whatever you are trying to make. For instance, you now know your efficiency will be 10% lower when you make a beer of this gravity... so you can adjust your ProMash efficiency to reflect that when you design high-gravity recipes.

Your efficiency is based on your setup and the amount of sparge water you are willing to rinse through the grains. That's why you can hit your efficiency if you sparge more and boil off the excess water you needed to use to rinse all the available sugars from the grain. I'm guessing this is the reason I haven't seen a calculation for this anywhere. There are just too many variables at work and the only way to know what you'll get is to understand your process and system.

On a side note, you'll never see it in ProMash because the author hasn't done any development on that product in years. That's not a knock on ProMash. I've tried the competitors and it's still my favorite brewing software... but it's a dead product.

 

[smurfe]

Brewing software will not "change" effincey settings based on the "type/style" beer you are making. If you enter 75% it will calculate 75%. Now, you have to actually have a 75% efficiency rating to have the software correctly calculate ingrediant levels.

To truly make your software work you have to know your average efficieny before you ever use the software. You have to do correct manual calculations for a few brews to see what your average is. When you know this average you enter that in your software. It will tell you how much ingrediants to add and as long as you don't make any changed to your brewing practices you should be close every time.

I also do not really agree that a BIG brew will have lower efficiency every time. This is simply not true and I rarely encounter this. It will happen though if you mash in too small of a vessel. That's why I asked what you mash in. If you try to mash a 5 gallon batch of 1.080 beer in a five gallon Rubbermaid cooler, it won't happen. If you do the same beer and mash it in a 15 gallon keggle, you will have no problem hitting efficiency. I have mashed 30 pounds of grain in my keggle and hit 90% efficiency which was an over shoot for me as I calculated 80% efficiency and had to end up making a bigger batch. On average though, most have to add DME as noted in the other post to hit gravity as the average batch sparge methods most use will not extract the grains full potential.

My no issue though is due to my system set up. I have a RIMS system so my system constantly circulates and I get great extraction. I still averaged 80% efficiency on 1.080 beers when I mashed in a 10 gallon Rubbermaid cooler with a slow fly sparge. After I did 4-5 brews I was able to calculate my efficiency as I hit 80% or so every time. I set that in my software and have no isses now. Prior to that I had it set at 75% and overshot every time.

So to condense all this babble. You have to know your system before you ever use your software to calculate a recipe. That take numerous brews with careful checking of efficiency and note taking. If you don't know the average parameters first, it will be of little value to you.

 

[Mike]

Isn't it a grist/water ratio of the mash, not the size of the mash tun size? As long as your mash fits in the tun at eg. 1.3 qts/lb, what does it matter? It seems like you're suggesting I use a more viscous mash, no?