A tale of two Brewzilla's

[hoppyscotty]

A Monday teaser for you...

A mate of mine and I have two identical Brewilla v3.1.1. They were bought only a few months apart. My mate bought his first and it was pretty spot on out of the box just using the default equipment profile in Brewfather. Basically nails the numbers every brew every time. Mine on the other hand always falls short by 5 and sometimes more gravity points so can be a significant miss. We are using the same measuring device (a refractometer) at both locations as we tend to brew together taking it in turns which unit we use.

I've made up for the shortfall in efficiency that I seem to suffer by creating a new Brewfather equipment profile dialling in a lower efficiency.

The question is on the basis we use the same grains, sometimes exactly the same recipes, same measurement euqipment, only live a couple of hundred meters away from each other, so same water supply and climate, why would the two identical devices result in different outcomes? The Manufacturing Engineer in me is flummoxed!

We've not tried swapping units which would be interesting, but we are planning to do a couple of double batches by looping the wort recirulation from one vessel to the other in a figure of 8 configuration and would be good if the two vessels performed equally as efficiently.

Ideas on a postcard welcomed.

Thanks.

 

[Caramel Ox]

As a suggestion - have you checked the mash temperature using an independent thermometer on both setups?

 

[Clint]

Are you a couple if hundred meters up a mountain?

 

[Sadfield]

What @Caramel Ox said.

Also where are you losing gravity points? After mash, boil or both. If you aren't getting the same boil off, could it be the difference in voltage in different locations?

 

[Deadhead]

How are you sparging? Are you doing it the same way? How about your HLT temperatures, are they accurate?

 

[Deadhead]

You definitely need to do this side by side - Since said 'manufacturing engineer', I'm going to talk engineering for a moment - You could easily do a proper DOE on this, varying your fixed and controlled factors - with location being a big factor, and obviously with the equipment.

 

[Agentgonzo]

Are you absolutely certain you're on the same water supply? I would expect you are, but water mains do traverse here and there so you could in theory be fed by two different sources. But I'd be amazed if it made that much of a difference.

+1 to verifying mash temperature of both setups with the same independent thermometer, but again I'd be surprised with a 5 point difference from a slight variation in mash temp.

Do you store the grain in the same way? Do you have your own mills? Mill gap can have a big impact on efficiency.

If you don't mill your own grain, do you use the same bag, or buy from the same place but at different times? Crushed grain will separate to a certain extent (like cornflakes in a box, the smaller bits end up at the bottom), so there was a comment a short time ago that the proportion of husk/starch (and this efficiency) might vary from bag to bag and even from the top to the bottom of the bag. But I wouldn't expect that to favour one brewer consistently over the other.

As mentioned, sparge regime (and temp) may vary between you and your friend. My sparge water heater is remarkably inaccurate with it's temperature.

 

[Agentgonzo]

Oooh, what about accuracy of scales? How do you measure (weigh) your malt? If one person's scales over/under read (cheap kitchen scales etc) then that could easily explain the difference.

Same for water I guess as well - do you measure your final wort volume? And strike/sparge liquor volumes the same way?

 

[clib]

Just swap machines and do an identical brew and see what happens. Same grains same crush etc.

 

[Agentgonzo]

Just swap machines and do an identical brew and see what happens. Same grains same crush etc.

Are you certain you have the same weight of grains? Did you use the same scales to measure it?

 

[clib]

Are you certain you have the same weight of grains? Did you use the same scales to measure it?

It wasn't me.

 

[hoppyscotty]

Been off line for a few days but thanks for replies.

I always measure pre-sparse, post sparge, check again just before the boil kicks in and of course OG. Usually off from the get go and pretty consistent...I can usually anticipate the OG from the post mash shortfall. Sometimes I've chosen to extend boil to compensate.

Location: definitely the same elevation! it's pretty flat around here and he's only a stones throw from me. I assume we're on the same water supply but I guess I could look into that to see if he might be on a different supply. One more thing to check.

The issue on mash temp and calibration...we've not done back to back with the same thermometer but both units maintain temp within the same, vague, way brewzillas do. I've not considered this because I hadn't thought that mash temp impacts extraction....the units will be within a degree or two between each other so nothing as much as 3 or more degrees I'm sure, but worth checking.

We have a number of repeat recipes so am pretty certain we're using the same recipes across both machines. The OG shortfall I get can range from being there or there about to being 10 points off. I can live with a couple of points adrift, but 10 points suggests something a bit more signficnant. Same refractometer in both cases.

On sparge, they're brewzillas so sparge I the same way. Not too precise about sparge water temp...usually pour heated water from a stock pot heated to around 75 ish degrees. Clearly it cools a few degrees through the sparge. But again, no issues at his place.

Currently we buy our grain ready milled from the same place. It currently lives at my mates place as he has a double garage, but in the past the grain has been moved between both places and when stored at mine his machine still does the business.

Think my next move will be to swap the units and see if the 'error' follows the machine or if it stays at the location.

 

[MickDundee]

The OP after reading all the replies to his thread:

 

[clib]

The OP after reading all the replies to his thread:

HE started it !!!

 

[DocAnna]

Hi just catching up.
Candidates for cause and elimination:

• Water supply, calcium ions and pH being the most significant variances that would influence efficiency - check with a pH meter, and add some extra calcium to be sure.
• Variations in grain type, storage temperature and humidity: buy a double batch and make the same recipe from the same ingredients to be sure.
• Strike water temperature. Denaturation of amylases can happen quickly within minutes. It’s not enough for you both to use the same strike temperature as it will also depend on storage and ambient temperature: if in doubt go low and warm up.
• Temperature with mash recirculating. The temperature during the mash will make a big difference and the the rate of recirculation will also make a difference: if in doubt mash longer if you want the wort to be more fermentable.

My bets are on water supply and the impact of strike temperature.

 

[hoppyscotty]

No worries on the Spanish inquisition.Its been niggling me so welcome any ideas or areas I've not thought of or didn't think would impact.

I've discovered the calculator on brewers friend that determine strike temp to ensure that you end up and mash temp once you've mashed in and seems to work pretty well over the last couple of brews where I've used it. Normally just heat up a few degrees above strike and mash in and turn the elements on so usually ends up a couple of degrees low by the time I've mashed in. Have wondered about denaturing of the enzymes and how long it takes but assumed you have to soak the grain and extract the starch before the enzymes wake up and start doing their thing.

Will defo check on water...I assume the same water...manage PH with a meter, but use Brewfather for additions based on the water companies annual water profile report, so might be different additions for his water.

Ta. will get there. Irony is over the last year I've built up a larger 3 vessel brewhouse at mine and that works bob on!! hits the numbers every single time. I've named it 'old faithful'!

 

[Sadfield]

On sparge, they're brewzillas so sparge I the same way. Not too precise about sparge water temp...usually pour heated water from a stock pot heated to around 75 ish degrees. Clearly it cools a few degrees through the sparge. But again, no issues at his place.

Do you both sparge in exactly the same way? And I mean exactly, same method, flow rate etc. Given the random nature of your results, I'd be drawn to channeling through the grain bed. Things like thermometers being out, would be a consistent error. Perhaps go no sparge for a few brews. And be weary of trying to eliminate too many hypothesis at the same time.

 

[hoppyscotty]

Well I've always thought the sparge is the weak point with these AIO systems because you can't control the sparge rate, which is an important parameter...it just runs through the grain at whatever speed it likes under gravity depending on how thick your mash is. So we have the top plate in place and maintain a quarter to half inch of water on top of the grain to avoid risk of channeling, so just topping up the level of water above the top plate. Having said that with some grain bills the water just runs through straight away the grist is so loose so you can't really build up that quarter to half inch of water above the top plate. I just use a litre jug to keep topping up the level.

The temp of the water is variable. I know not to have sparge water warmer than about 80 degrees, and has to have some temp in it to improve its impact so aim for the mash out temp of 75 degrees but in reality could be cooler than that or a few degrees warmer.

 

[dave_77]

I have been have been having a similar issue for the last few months. Previously it was always pretty much within 1-2pts up or down for pre boil gravity and I could usually adjust it by the end of the boil to be pretty close
Recently I have had some batches 2-6 PTS down very rarely over, by the end of the boil I have been down still even with some extra boiling.

I had looked at the last 20 brews to see what the average mash efficiency was and it seemed to vary between 66%-75% so I adjusted the brewfather profile to 72%. I had noticed a lower efficiency when using Bestmalz Pils malt compared to Crisp MO. The last brew with this amendment, still 3 PTS down
I have also been looking at the total water , boil off and the minimum dead space as I drain from the tap now. Next adjustment is a reduction in the total water by 1 litre as on the last brew I had 1 litre extra in the fermenter and also the mash pipe still was had wort dripping so am I using to much water for the grain/batch?

I have also noticed that when the sparge runs straight through the grain, the efficiency is usually down and like you say it's so random when that happens.

When I used to batch sparge in a grain bag I used to hit the numbers more regularly.

 

[parpot]

Faulty 30amp Boil Switch, I had one this week and had to swop it out?