Debrief on Hefeweizen brew-day with Grainfather

[Matt Poff]

Had a mammoth brew day/night yesterday with my second GF brew - a higher gravity Hefeweizen loosely cloned from a festival version of an Erdinger beer - target O.G 1058. The recipe had a fairly fussy mash schedule so it was a bit of a baptism in fire but that's what I was after to stretch me as well as the GF. Unfortunately extraction and efficiency results weren't great compared to the first brew (Behemoth Chur!) - I'm estimating 63% compared to around 73% for the first brew. Had to boil-off 4L to get wort within the target ball-park (achieved 1055). Possible reasons I can see:

1. Had to substitute Gladfields Pale Wheat Malt for Weyermann's at last minute as HBS was out - although seems similar in terms of extraction efficiency.
2. I didn't push the overflow pipe down flush with the top perf plate. On one hand you'd think this would deliver higher extraction as all the liquor flowed through the grain but perhaps the overflow creates circulation that aids extraction? 
3. The aforementioned overly fussy and inefficient mash schedule - ramp up times were very slow and erratic (see below).
4. My sparge water temps fluctuated between 65-81C owing to of non-regulated temp control on sparge (pot on gas).
5. Possibly screwed up pH - I used this Brewersfriend calculation to hit for pH of 5.2 which meant a 7g addition of CaSO4 and 6g of tartaric acid.

The other major PITA was the chiller. I had tap water running at 11˚C and let the wort run cold before draining into FV and took temp on a gravity sample of 17˚C about 10L but the final FV reading was 30˚C and it took an age to cool it for pitching. I used Wyeast 3068 which says to pitch below 22˚C but I was falling asleep on my feet near the end and pitched somewhere in the 22-25˚C range (depending where you took a reading). 

On the plus side - the sparge was fluid, colour good and the green beer tasty so provided it ferments it will hopefully still be a tasty number.

Here's the fussy mash schedule and the actual measured ramp up times (some took as long as the rest duration).

Name                   Description                             Step Temperature   Step Time    
Mash In                Add 17.81 l of water and heat to 43.0 C 43.0 C             15 min       
Beta-glucan rest       Heat to 49.0 C over 15 min              49.0 C             15 min       
Sacrification          Heat to 66.0 C over 27 min              66.0 C             35 min       
Mash Out               Heat to 78.0 C over 3 min               78.0 C             10 min


This was done inside in a laundry with ambient temps around 15-18˚C. Ramp ups using the mash 0.5kW element were painfully slow. Switching to the 2kW sped up the process (I measured +1.15˚C/m earlier when prepping some sparge water) but switching back to the mash element the displayed temp would drop 2-3˚C again so it was impossible to get a consistent ramp. Best I could do was periodic switching between the two elements until within +-2˚C of the target before leaving on mash setting for the temp to settle.

Interested to know if others have experienced similar difficulty with multi-step mashes and managing temp changes and issues cooling the wort sufficiently. The second one really puzzles me as I got 24˚C into the FV on the first batch and that was done mid-afternoon on a sunny day not 11PM on a chilly night. 

General observation is that grain bills around 6.5kg seem to be the sweet spot for a 28L batch. If I do this again I've calculated it for 65% BH efficiency which ramps grain additions up to 6.42kg for the recipe. Interesting that the Chur kit supplied with the GF had a similar size grain bill and a 75 min mash for a similar O.G target.

Also tweaked my boil-off settings in BeerSmith to 2.34L/h based off recorded measurements.

Any comments, insights most welcome! Would be interesting to brew this again down the line and see how efficiency can be improved - particularly the time taken to brew the thing!

[Dene McDonald]

A nice detailed debrief. 

I'm a little disappointed to hear about the trouble with ramping between steps. I'm coming from a ramp and soak PID controller that could effortlessly step between mash temps. The only concern I would have about setting it to the 2kw heater is that if the recirc rate isn't fast enough the grain may get overheated at the bottom causing phenol flavours. I've experienced this in my first biab setup, although I was using 2x 2.4 kw elements on full power without a false bottom! Worth experimenting with as the only bad thing that can happen is one batch might be slightly tainted if it doesn't work out.

I've been fairly vocal about the poor specs of the chiller and plan to sell mine off and use my existing immersion chiller - it's a powerhouse that can chill a 25 litre batch from boil down to 19 degrees in about 15 minutes. I plan to recirc into the grainfather and whirlpool at the same time. I hope the company realise that the chiller is a pain and offer either an upgraded model or an immersion chiller as an alternative. The pump is definitely powerful enough to handle a decent counterflow to allow recircing back into the pot for a whilpool.

[Matt Poff]

Yeah will have to wait and see with possible burning issues - no evidence of it on the bottom of the kettle anyway. Your chiller set-up sounds ideal will be interested to see how that goes. Is it copper or stainless? Those Chinese plate chillers look worth a crack too at the price.

With the ramp-ups, other than replacement with a PID controller that can intelligently calculate temp adjustments based on volume can't really see an option other than to get practiced at jockeying that element switch!

[Dene McDonald]

It's a stainless chiller. Easy clean and looks good!

[Peter Smith]

I think variation in the milling could easily change eff by a few %,  also when you did the sparge did the sparge water cover the bed or run through quickly ?  approx how many mins did the sparge take and how many L ?

going to take a long time to step if on the 500w setting....

Dene this looks interesting

http://www.trademe.co.nz/Browse/Listing.aspx?id=789481748

[Dene McDonald]

You can get those for a fraction o the price on Aliexpress.

http://www.aliexpress.com/wholesale?SearchText=plate+chiller

[Matt Poff]

I discussed a second pass through the mill for the wheat malt with the HBS but decided against it until I saw how well the GF sparged. I sparged with approx 15L of water over an hour from initial pour to removal of the basket. The sparge water flowed through pretty well, I needed to keep a very slow poor going to keep the recommended cm or so above the grain bed. End of sparge runnings gravity was around 1.020.

It's finding the balance between over-ramping with 2kW and sluggishness of the 500w.

[mattd2]

Would be interesting how they are getting 2000W and 500W out of the same element, anyone know?

[Richard Jack]

2 ways to do it -  there could be  2 1kW circuits in the element and they are switched between series (500W) and parallel (2kW). Which is interesting because it means that with a bit more thought and a 3 way switch they could have have a 1kW mode too. I would have thought that would be too good to pass up on the design side so I suppose there must be 2 elements? 

[John H]

What % wheat malt did you use in your recipe. My last wheat, (which was BIAB) had 44% wheat and I only got just under 60% Mash efficiency so don't feel too disheartened.

When you did your step changes - was the pump on or off?

I found I needed to do the step changes on full power, and only switched to Mash element when it was close to target.

[Matt Poff]

Wheat malt was 56% of grain bill so maybe not so bad. I had the pump on through the step changes and started switching to full power but found when I switched back within 1-2˚C of target to the mash setting the measured temp would also drop back 2-4˚C sometimes. Started overshooting 1-2˚C to compensate.

[Chris]

When recircing you are suppose to leave the 2kw element on.

What is basically happening is the heat from the bottom gets pumped on top of the grain and heats the grain. If it goes above that is fine because the temperature is read from the bottom where the heat source is, not the grain itself. Once the temperature has been above or on target for 2 mins then switch to 500w.

Or you will undershoot by a couple of degrees because your grain will not be at the same temperature as the bottom of the kettle.

Don't panic with it going 2 degrees higher because this isn't the grain itself :).

I didn't have a problem with the cfc i actually found mine cooled to well. But the water out in Burnham is cold as hell and i had the cfc with no restrictions. Recirc into the GF to let it lower temperatures first then into the fermenter. Experiment and take good notes and you will have it down.

Doing a porter next week will let you know how it goes eff wise. Chur was  73% brew house efficiency for me.

[Dene McDonald]

Aren't you supposed to switch it to mash when you are recircing? I'm guessing you mean switch it to 2kw when ramping?