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!

[Chris]

no you only switch to mash once the temperature has been at or above the required temp for 2 or so mins to ensure the grain gets to the same temperature.

You do this between stages too. the whole reason behind the 500w is that it maintains that temperature but is horrible for getting the grain upto the right temperature first.

It was in one of the grainfather making beer video.

https://www.youtube.com/watch?v=j0rIV0wCokE

[Matt Poff]

Just re-watched a bit of the video. My understanding of that video was that staying with the 2kW to hit mash temp was just to compensate for the increased thermal mass of the wort after adding your grain bill (i.e. just for use during the mash-in). He does flick over to 2kW for the mash-out and says to leave it there and also says "this is how you also do step-mashing". I guess in practice for a step, you just have to let the 2kW climb a couple of degrees over the set target for a half minute or so and switch back to 500w.