Equipment change and loss of efficiency, why?

[Anmetcalf]

For years I have been doing biab with 90-minute mashes in a stainless steel mesh basket and NOT recirculating and have consistently got 70% efficiency. Now I switch my basket to a solid side basket and added a pump for recirculation. I have done two batches since the upgrade. The first batch I recirculated the whole time a my grain bed became very compacted and I actually had to stir it to keep it unpacked it so it could circulate water and I got 65% efficiency. The second batch I stirred and ran the pump every 15 minutes and during that time I ran the element to maintain my heat. I didn't stirred at the very end for the last 5 minutes this time my grain bed stayed loose the whole time but I only got 60% efficiency. Also both batches were mashed low @ 145°.

I have not changed my grind from when I used to not recirculate so my mill is still set at .035". Also for reference I got a 15 gallon pot, pump for recirculating it's electric brewing system so I'm able to maintain my heat and I do full volume mashes.

Now my question, what do I need to change to help that efficiency? I was quite surprised my efficiency was actually lower I actually thought right off the bat I'd at least be at 70% maybe even 75% but to have it go down is quite surprising to me.

 

[Vale71]

I can only recommend wet conditioning before milling. Just measure 2% water in weight and sprinkle on the malt mixing thoroughly, shortly before milling. Ever since I switched to a RIMS system I always do that and never had issues with the grain bed compacting.
As you already guessed your drop in efficiency is most likely caused by recirculation compacting the grain bed and preventing some extract from being efficiently washed out of the grains trapped in the center of the bed.

 

[LittleRiver]

...biab... mesh basket and NOT recirculating...70% efficiency... I switch my basket to a solid side basket and added a pump for recirculation....grain bed became very compacted and I actually had to stir it ... got 65% efficiency...stirred and ran the pump every 15 minutes ... ran the element to maintain my heat.... got 60% efficiency.... mill is still set at .035".... I do full volume mashes. Now my question, what do I need to change to help that efficiency?...

First thing would be to reduce your mill gap.

Regarding the pump, if you are honest with yourself you can see that its main contribution is to cause you hassles.

You are doing a full volume mash but the basket is segregating a portion of your water from your grains. I use a bag, not a basket, for that reason.

I grind at .025", insulate the kettle during the mash, don't sparge, and get low 80's efficiency. My brew days are hassle free.

 

[RM-MN]

Also both batches were mashed low @ 145°.

At 145 degrees F. your mash was outside the "Brewers Window" so far that the alpha amylase was barely working. Bring your mash temperature to 148 and I'll bet your efficiency jumps.

Next step to increasing efficiency is to mill the grains finer. If you mash for 90 minutes and only get an average of 70% efficiency your grains are way to coarse. I typically get over 85% with a 30 minute mash.

 

[Big Monk]

At 145 degrees F. your mash was outside the "Brewers Window" so far that the alpha amylase was barely working. Bring your mash temperature to 148 and I'll bet your efficiency jumps.

Next step to increasing efficiency is to mill the grains finer. If you mash for 90 minutes and only get an average of 70% efficiency your grains are way to coarse. I typically get over 85% with a 30 minute mash.

145 is actually a great temperature to do your beta amylase rest, especially in a multi-rest mash, provided the gelatinization temperature of the malts used allows for it.

The Hartong Index is a good indicator of what the gelatinization temps for the specific malt are.

 

[jack13]

Everyone says the mill gap is the most important factor in efficiency. It has been my experience that everyone is correct.

As for the suggestion about conditioning your malt. If you go that route, I'd go with something like this to spray the water rather than your basic spray bottle:

https://www.lowes.com/pd/Project-Source-0-396-Gallon-Plastic-Tank-Sprayer/3711310

 

[Big Monk]

The first batch I recirculated the whole time a my grain bed became very compacted and I actually had to stir it to keep it unpacked it so it could circulate water and I got 65% efficiency.

Are you throttling the pump? You may need a valve on the outlet partially closed in order to reduce the flow rate going through the pump so you don't compact the grain bed.

 

[mongoose33]

Are you throttling the pump? You may need a valve on the outlet partially closed in order to not pull more wort on the outlet then is being reintroduced to the grain bed.

How can you pull more wort at the outlet than is being reintroduced at the grain bed? Where else can it go? I'm missing something here.

 

[Big Monk]

How can you pull more wort at the outlet than is being reintroduced at the grain bed? Where else can it go? I'm missing something here.

That was a bit of a word salad. Sorry. See my correction above.

If you pull too hard on the output of the pump, you'll tend to compact the grain bed more and stick the mash. If you throttle the output and lower the flow rate, you'll mitigate this issue.

 

[kevin58]

Every change in equipment is going to result in some changes in your efficiency. When you get a new system you pretty much have to start from scratch figuring out the best way to use it for the optimum efficiency you can get out of it.

 

[RM-MN]

145 is actually a great temperature to do your beta amylase rest, especially in a multi-rest mash, provided the gelatinization temperature of the malts used allows for it.

There was no mention of a multi-rest mash. That was why I thought the temperature was a problem.

 

[CascadesBrewer]

I grind at .025", insulate the kettle during the mash, don't sparge, and get low 80's efficiency. My brew days are hassle free.

As somebody that just ordered a Brew Bag and winch, I like the sound of that. I have a nice 10 gallon stainless pot...so why am I mashing in a cheap enamel coated pot and lautering in an insulated bucket???

Is it important at all to set my mill (Barley Crusher) with feeler gauges or can I just play around until it looks good.

 

[Big Monk]

There was no mention of a multi-rest mash. That was why I thought the temperature was a problem.

Right. I was just commenting on the graph you put up.

145 is actually a great temperature for a single infusion since it's optimal, in both temperature and enzyme activity, for beta amylase. However, higher gelatinization temps can often times make it unsuitable.

In many cases, even this one for instance, that may have happened.

So I agree with what you are saying 100%.

 

[LittleRiver]

...Is it important at all to set my mill (Barley Crusher) with feeler gauges or can I just play around until it looks good.

You could play around with it, judging by the looks of your crush whether or not you have it right. You can even post photos of your crush to get feedback.

But I think feeler gauges are the better way to go. That way you know exactly what your setting is, and if you ever change your setting or disassemble your mill you can reset it exactly.

 

[Anmetcalf]

At 145 degrees F. your mash was outside the "Brewers Window" so far that the alpha amylase was barely working. Bring your mash temperature to 148 and I'll bet your efficiency jumps.

Next step to increasing efficiency is to mill the grains finer. If you mash for 90 minutes and only get an average of 70% efficiency your grains are way to coarse. I typically get over 85% with a 30 minute mash.

This is what I was beginning to think, that my mash was too low of a temperature. Being that I changed my equipment and tried to do this low temperature mash at the same time it threw me for a loop.

On my old system I would get 70% with a 90 min mash with no recirculation, and milling at .035. That system gave me a fair amount of trub and I'm hoping my new system with the recirculation will help to trap that fine grain particals on top of the grain bed. My next batch I will be mashing higher.

I was recommended, by the manufacturer of the equipment, to change my mill to .045-.050, which I am worried will not help.

 

[doug293cz]

What is the diameter difference between your kettle and the basket? With a solid sided basket, the liquid between the basket and kettle wall does not participate in recirculation, so the wort there is very likely to be less concentrated than the wort in and under the basket. This means the wort in the basket along with the grain is more concentrated (higher SG), and when you drain the basket the wort retained in the grain is the highest SG that you had in the mash, so excess sugar is retained in the grain, lowering your lauter efficiency. The larger the difference in diameters, the larger the fraction of the wort is in the dead area for recirculation, and the higher the SG of the wort inside the basket. This may be a contributing factor, in addition to lower conversion efficiency due to the very low mash temp. So you could have reduced your lauter efficiency and your conversion efficiency at the same time. Since mash efficiency is lauter efficiency times conversion efficiency, lowering both is a double whammy.

Brew on

 

[Anmetcalf]

My basket is about 15 ¼" wide and my pot is 16¼" inside diameter. I am also able to crank my pump up if I desire and pull most that liquid out of the sides, but it is a small amount.

 

[doug293cz]

My basket is about 15 ¼" wide and my pot is 16¼" inside diameter. I am also able to crank my pump up if I desire and pull most that liquid out of the sides, but it is a small amount.

If the wort level during the mash extends 8" up the side of the basket, then the volume between the basket and kettle wall is 0.85 gal. Not a huge amount, so the effect I postulated is probably a minor contributor to your lower efficiency.

Brew on

 

[keggert]

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