The first Hefeweizen experiment was a really great learning experience and it seemed to be well received so why not do another? After doing pitch rate variations, it seems the natural next step is temperature. So, I ran the experiment the same way as the first – make a 3+ gallon batch of hefeweizen wort and split it across three different one gallon jugs – but this time I placed the three fermenters in three different but identical chest freezers with identical temperature controllers but set at 3 different temperatures (62F, 66F and 70F) to see if all other things are equal what is the impact of fermentation temperature. Here is the recipe that I used (same as last time but Munton’s Wheat DME and Hallertau hops rather than Briess Wheat DME and Spalt hops).
Beer Name: hefeweizen test ebiab 2
Author: dennis pike
Original Gravity: 1.050
Final Gravity: 1.013
Alcohol: 4.9 %
Bitterness: 10.3 IBUs
Mash Fermentable Weight: 4.15 Pounds
Strike Water Qty: 4.08 Gallons
Mash Volume: 4.41 Gallons
Kettle Gravity (start of boil): 1.042
Starting Boil Volume: 4.125
Boil Duration: 30 Minutes
Evaporation Rate: 1.25 Gallons per Hour
Final Boil Volume: 3.5
|Weight (Lbs)||% by Weight||Name||Yield||SRM|
|4.15||100.0||Muntons Wheat DME||91.3||8.0|
|Weight (ozs)||Name||AAU||Time (mins)||Use||IBUs / Addition|
|.85||German Hallertau Pellets||2.7||30||Boil||10.3|
Yeast and Friends
|1 vial||White Labs WLP300 Hefeweizen Ale|
|.5 tsp||Yeast Nutrient (Wyeast)||10|
hefeweizen test 2 is to see effect of fermentation temperature. 0.5L starter with 50g of DME and 1 vial of WLP300.
WLP300 was lot 1015489 with good test results on 3.23.2015. 4 months old? not sure if test date correlates to ship date.
this starter should contain ~ 150 billion cells
pitch rate is 50% of standard rate or .375 million cells / mL / degree Plato
so 1.050 is 12.5 Plato and 1 Gallon is 3785 mL so that is 375,000 x 3785 x 12.5 ~= 17,700,000,000 = 17.7 billion cells
so to get 17.7 billion cells I would need ~ 59 mL (rounded to 60) of the starter into each 1 gallon fermenter
I am doing 3 x 1 gallon test beers all from the same wort (1.050 wheat dme with 10 IBUs)
pitch rate is 0.5
beer 1 temp is 62F
beer 2 temp is 66F
beer 3 temp is 70F
will take remainder and test cell count to see how close i was
Temperature at Bottling: 72 F
Volumes of CO2: 3
Amount of Beer: 1 Gallons
Amount of tableSugar to add: 33.1 grams or 1.2 ounces
[End of Recipe]
Some items of note from the experiment:
1> I don’t have a good way to do thermowells in the 1 gallon jugs so I taped temp controllers (Johnson A419s) probes to the side of the jug and then covered the probes with foam insulation. So, it is likely that the internal temperature of the beer was higher than the set point during the peak of fermentation.
2> the wort was cooled to 70F and then the 3 jugs were filled and placed in their fridges. Once all three were stable at their fermentation temps, I pitched (~4 hours later). So, the 62F beer was pitched at 62F, the 66F was pitched at 66F and the 70F beer was pitched at 70F.
3> I mispoke on BBR – I didn’t use pure oxygen for these, they were just shaken vigorously for 30 seconds.
4> all three had fermentation activity within 24 hours but the 70F had a huge kreusen at 20 hours and the 62 and 66F beers didn’t get that active for 36 hours.
5> they were all left in their ferments for 21 days, they all finished at 1.013 (also mispoke on BBR) and they were all bottled at the same time with the same amount of bottling sugar (32g of table sugar per gallon) targeting 3.0 volumes.
My wife and I did a tasting and took our notes, I sent of bottles to James @ Basic Brewering Radio and I took bottles to my homebrew club where 16 member filled out a questionnaire that asked for overall score, hefeweizen qualities score, general impressions and flaws. the main thing with the scores was to keep them relative so the score is important but most important is that the beers are scored in the correct order so I know which was most and least favorite for each club member.
I consolidated all the questionnaires and you can see the results here:
And the totals on preferred beer is (1 = 62F, 2 = 66F, 3 = 70F):
In general, I found it very difficult to tell the 62F and 66F beers apart but the 70F stood out to me because it did have some minor, what I would call “chemically”, off flavors. You can see in the overall impression comments that, counter to what I would have thought, the 62F had the most pronounced banana esters, 66F was more balanced and 70F was all over the map. 62F and 66F got no real flaws mentioned other than being out of balance (too much banana) but 70F had all kinds of flaws listed. I will say that, to me, I also got these flaws but they were background. Noticeable but you had to kind of search for them. None of these were “bad” beers but 70F was the only one where I was picking up “flaws”.
My take aways from the first two experiments:
1> pitching rate has a pronounced effect. it seems that around half the standard pitch rate is a good place to start (0.375 million cells/ mL / degree plato). If you want more esters go with a bit lower pitch rate, less esters go with a higher pitch rate. 0.375 pitch rate works out to about a vial/smack pack in 5.5 Gallons of wort but it is important to note I grew up a starter and then pitched the amount I wanted from the starter.
2> temperature also has an impact but it would seem that lower give you more banana and higher gives you more of other esters (apple, wine, floral) that detract from the banana and as you go even higher likely is generating hot alcohols and unpleasant acetate esters. from my sampling it seems in the low 60s (62-66) is a good starting point > lower (i know….weird!) for more pronounced banana and higher for more balance.
other parameters to consider (possible future experiments!)
- ferulic acid rest : at 111F (44C) , wheat and barley malt will generate ferulic acid which hefeweizen yeast will then convert to the clove phenol (4VG) during fermentation.
- oxygenation: the theory goes that less oxygen with generate more esters and more oxygen will generate less.
- bottle conditioning vs forced carbonation: bottle conditioning is supposed to generate higher esters and phenols.
A great presentation from the MBAA on the science of Hefeweizens is here: