Testing hefeweizen pitch rates

[Sadu]

I haven't had much success with hefeweizens so far, with the last one being almost undrinkable. I'm determined to get this style right.

Since I brew 1 gallon batches and use 3x 1/2 gallon growlers to ferment in, this is a good opportunity to do some 3 way testing.

Today I'm testing hefeweizen pitch rates - the general vibe is that you should underpitch "a bit", maybe by 25%, but that's hard to measure when pitching from slurry and you don't really know how many cells you have. Basically if you guess wrong on the yeast density calculator, your pitch rate will be way out. Others say to "abuse the yeast" for best results.

My yeast was bought new couple of months ago, I overbuilt a starter and put the extra in the fridge. This is that extra slurry, rebuilt into a fresh starter over 4 days in 2 stages, then left to settle in the fridge for 2 days then decanted. What is left is reasonably thick, freshly built yeast with little non-yeast matter in there. This is the baseline I'm working from and will be what I use next time I make a hefe.

MrMalty and Beersmith say I need 42 billion cells for the whole batch, I have assumed 2.5b cells per ml on the basis that it's pretty good quality yeast and somewhat thick.

I pitched this amount:
- 7ml (approx what Beersmith and MrMalty recommend for an ale of this gravity).
- 4ml (bit of an underpitch)
- 2ml (big underpitch, should still be an underpitch even if I guessed wrong on the cell density)

Basic details:
- OG 1.050, 4.5 litres split 3 ways.

- Yeast is Wyeast 3638 - (HBS didn't have 3068, this is what I got, if it sucks again the next split test will be yeast).

- Fermenting at 68f / 20c. I want a good hit of banana and fermenting at 62f hasn't worked for me so far. Fermenting in temp-controlled swamp cooler with the probe in the medium-pitched growler.

- I didn't aerate - other than a light swirl to mix in the yeast and whatever aeration happened when transferring.

- Recipe is a little non-standard - 50% wheat, 35% Pils, 10% Vienna, 5% caramunich. I wanted a bit of darker stuff because the last hefes were insipid pale looking things, I want something that looks more like an IPA. Also wanting to lower the pH a bit with the darker grains, so I can avoid acid malt.

- Water profile is soft, slightly adjusted to get calcuim to 50ppm, adjusted sparge pH to 6 with lactic acid. Mash pH was measured at 5.7 after 20 mins using a cheap meter. It most likely was slightly lower than that. The last hefe was almost dumped due to too much acid, so I erred on the side of caution here. 1% acid malt would have got me closer for next time.

I'll update this thread once fermentation starts, and get some pics when there's something to see.

 

[JGF]

Subscribing...

I prefer the 3068 Weihenstephan yeast over the Bavarian but both will work.

 

[Sadu]

Here are the 3 growlers after pitching.

 

[Sadu]

10 hours since pitching. We have liftoff!

You can clearly see which growler got more yeast than the other ones. Airlock has just started bubbling in the 7ml growler, krausen just starting to form on the 4ml, no real signs of fermentation in the 2ml yet.

I'm beginning to think that this might be less of an underpitch than I was hoping for :smack:

 

[Sadu]

19 hours since pitching. Krausen and subdued airlock activity on all 3 fermentors. Don't have a photo but 2ml looks like 7ml did in the last photo and 7ml/4ml has darkened and thickened a bit. Certainly none of these look like anything other than normal fermentation to me.

To put this in perspective, the 2ml in 1.5 litres scales to 30.5ml in a standard 23 litre / 6 gallon (in the ferm) batch - or 2 tablespoons. This is good quality slurry, freshly built then decanted, with limited non-yeast matter - but I would never dare to pitch only 2 tablespoons of slurry to a standard batch and expect a lag of under 24 hours. If nothing else this experiment gives me more confidence in pitch rates.

One thing to note is these growlers never give wild fermentations - forget about blowoff tubes - I am yet to see more than an inch of krausen on top and airlock activity never gets more that a blip here and there - even when pitching a lot more than this. I think it's just such a small volume that the airlock easily takes care of the overload.

 

[ThatITGuy]

Subbing in for this one, should be interesting! I'm a big fan of any style wheat beer, I've yet to brew my own though.

 

[meatcleaver]

sub'd. curious how this'll turn out.

 

[thereverendmaynard]

That PH seems very high. Do you also know what your wort ph was at the end of the chill? I have been going towards lower pitch rates and less O2 in my hefe's as well. I was also reading that PH under 4.8 or so in the final wort will preclude clarification. I was considering for my next hefe to add a bit of citric acid with 20-30 minutes left in the boil to get a lower final PH.

I typically target 5.3 (at room temp) for my mash PH ~ 5-10 minutes after dough in.

 

[Sadu]

That PH seems very high. Do you also know what your wort ph was at the end of the chill? I have been going towards lower pitch rates and less O2 in my hefe's as well. I was also reading that PH under 4.8 or so in the final wort will preclude clarification. I was considering for my next hefe to add a bit of citric acid with 20-30 minutes left in the boil to get a lower final PH.

I typically target 5.3 (at room temp) for my mash PH ~ 5-10 minutes after dough in.

Yes it is on the high side, but there's a reason for it.

A while back I was having trouble getting a water report so I thought I'd be clever and start adding some acid malt to some brews - on the assumption my water is pretty soft and small adjustment is often necessary in lighter beers and maybe it would help (you never know until you try).

What I discovered is this:
- For the most part (IPA / APA / Blonde / Helles / Pilsner) a bit of acid malt helps slightly, or made no difference.
- Hefes / Dunkelweizens taste real nasty tart bad with 2% acid malt, right on the borderline of dumping them.

Interestingly, I plugged the nasty tart hefe into Brun'water and it said the pH should be right in the sweet zone, 5.35 or thereabouts. I suspect I have a lower taste threshold to lactic acid than most people so with that in mind I'm aiming for the high end of the range.

 

[Sadu]

Update at 24 hours since pitching. Airlocks busy on all 3.
The proof is in the tasting, but nothing about this says underpitch to me. I may have to repeat the experiment using fractions of a ml.

 

[Oldskewl]

Subbed! First attempt at a Hefe was almost a dumper. Used 3068. Reeked of sulfur. Probably overpitched, oxygenated and kegged too early.

 

[Horseflesh]

I have very soft water and Beersmith estimates my mash pH as too high for this style. Nonetheless, using 3068 at 66F, my hefes come out well.

Curious to see how this comes out. I've used a starter and just pitched a pack and could not really tell a difference, but I was not fermenting and tasting side by side.

 

[Dcpcooks]

From my and my clubs experiments with heffe's I'd slightly underpitch. A step mash with a rest at 113 will do wonders if you have the ability.

 

[redking11]

Subscribed, I'm in the pursuit of a banana and bubblegum forward wheat/Weihenstephaner clone. I wish you were doing typical 5 gallon batched with standard smack packs or something that made it easier for us to duplicate if you came up with something you liked.

 

[jjeffers09]

I don't understand the puzzlement with this style. I do understand you are far from the only one who has come to that point though that they can't seem to crack the code. Here is my advice...

If you're treating your wheat yeast as special as any other brett, lambic, lager, saison yeast you shouldn't have any issues. Each strain obviously has its ideals, but Bavarian wheat yeasts need lots of O2, they perform best in shallow and open fermentations. A fermentation square. Like the fish gutter on brewing tv. I have used totes from the hardware store, the ones that snap shut. Keep them open for the first 72hrs, keep the depth of the wort to ~4-5" max and pitchrate should be between 0.75-1.0.

Hefe yeasts struggle under normal pressure in a normal fermentation carboy or bucket. The yeast likes to take a nap every 12hrs or so, give an agitated stir and let the yeast raise up 2-3 times then close off the fermentation. I like to skim for a top crop for my next batch at that point. However don't fear the open fermentation. Worse comes to worse, and you are ferementing with gnats and flys, cover the square up with cheese cloth to keep dusts and critters out for the first few days.

 

[Sadu]

Subscribed, I'm in the pursuit of a banana and bubblegum forward wheat/Weihenstephaner clone. I wish you were doing typical 5 gallon batched with standard smack packs or something that made it easier for us to duplicate if you came up with something you liked.

Yes, it is more of a challenge working with an unknown starting point. I can't afford a smack pack each time so that option is out for me, plus I like doing 1 gallow batches until I'm happy with a recipe and only then scale it up. But even with a normal smack pack you have unknowns about the viability of the yeast and how it's been stored/transported

However - I do think that this process can be replicated from batch to batch for a consistent pitch amount.

• Take a smack pack and make it into a starter
• Put it in the fridge until you need it
• Prior to brew day, decant the yeast, make a fresh starter
• Give it 2-4 days on the stirplate to freshen up the yeast and build a good amount of new cells
• Back in the fridge for 48 hours
• On brew day decant off the used wort and carefully measure the thick slurry for pitching

My logic (for better or worse) is that a consistent process will yield a consistent yeast thickness and a fairly consistent viability. Over time there will be a build up of dead yeast but if you are pitching at least half of the yeast each time then you are clearing the dead stuff out as well. Because this yeast is fresh from a vial there are no hops to factor into the equation. I get just a tiny amount of trub since I use real-wort starters, but with DME that would be less of a factor.

 

[Sadu]

48 hours since pitching. All 3 fermentors look pretty similar at this stage.

I took a small taste sample from the 7ml version and straight away got hit by a lactic sourness. This is very frustrating because my last 5 gallon hefe was ruined by this taste and it didn't get better over 8 weeks or so. Last time it was sourmalt in the mash that wrecked it (as far as I can diagnose), this time the only pH adjustment was a small amount of lactic acid in the sparge water. All other indications point to high pH so I don't really understand why this lactic flavour is so prominent in this style, but not in others.

But that is another issue - hopefully this doesn't mask the other flavours that I'm trying to test for in this pitch rate experiment, although I suspect it will.

 

[Horseflesh]

You could try phosphoric acid instead, which is supposed to be more neutral in taste.

 

[Sadu]

4 days since pitching. Krausen has dropped on all 3 fermentors. Looks like a pale ale, which is just the colour I wanted. I took a gravity reading on the 2ml sample and it's 1.011, the others will be that or lower. FG for this recipe is 1.012 but my brews have a tendency to go a bit lower than what Beersmith says.

Taste is pretty similar to the last hefe fail. A tart sourness masking all other flavours - although I was getting a bit of fruityness shining though in the small sample I took. Basically, I'm a giant ********* for adding lactic acid to the sparge, and I should have known better. Even though the pH was on the high side, there is just something about lactic acid + hefeweizens/3638 yeast + my palate that is not compatible. I have phosphoric acid on the way here from America which will be a few weeks away, I couldn't find any for sale in New Zealand which I find unusual.

This video comes to mind...
[ame]https://www.youtube.com/watch?v=eKgPY1adc0A[/ame]

Anyway, I'm not sure if I will be able to taste the difference between these 3 samples due to the sour flavour, but I'll give it a few days then bottle the batch and see this through.

But I think the experiment has proved worthwhile regardless.

Let's look at the 2ml fermentor:
- Less than 19 hours lag time before visible krausen
- Reached FG in 4 days

Would we call this an underpitch? I'm not sure that I would. Seems to be a pretty solid fermentation to me, and I'm surprised by that.

I am planning to repeat this experiment I think, but use less yeast next time. I'll try to get the yeast in the same condition, then pitch a smaller amount - maybe 1.5ml, 1ml, 0.5ml in each 1.5 litres of wort and see what happens. And skip the pH adjustment next time. I'll probably keep the recipe the same, unless anything changes in further tastings.

 

[meatcleaver]

the best weizenbiers I've made were direct pitched from smack packs that got hot in transit or repitched from very old slurry. these took anywhere from 36-60 hrs to get started. I'm convinced it's that reproductive phase that really contributes the most to those banana esters. temperature plays a part of course, as warmer temps encourage the yeast to have a full blown orgy & cooler temps keep this in check.
I wouldn't consider the 2ml sample under pitched. personally, instead of pitching 25% less than recommended, I'm planning to pitch 25% OF the recommended amount.

 

[redking11]

Next Time I do a wheat I think I am going to use 1/2 a smack pack and then if it's not fermenting within 5 days I'll pitch the other 1/2. But 1/2 a smack pack sounds like a very small amount.

 

[Sadu]

Bottled this today on day 10. Didn't do any secondary / cold-crashing / gelatin since cloudiness is a good thing here. Used a carbonation drop in each 12oz bottle and got a whole 3.5 bottles from each growler.

To much surprise, the one with the most yeast (7ml) finished highest at 1.013 and the others (4 and 2ml) finished at 1.012. Didn't see that coming.

Wait you say, didn't the 2ml sample reach 1.011 like a week ago? Well yeah, but I suspect that was simply a bad reading. When I take an early gravity reading if there are bubbles in the way I just guesstimate. With these small batches I put the gravity sample back in, so I don't want to blow on it or touch it more than necessary.

Anyway, at this point in time the biggest problem is the lactic sourness. Sadly it's masking most of the flavour and it's not nice, smells bad too, just like last time. I don't want to get sidetracked by this since it's not what I'm testing, but it is making it hard to pick flavours. Will skip all pH adjustment next time.

While these carbonate I'm going to prepare yeast for a repeat experiment next week. This experiment has proven that 2ml per 1.5 litres of this yeast is not an underpitch so I will repeat with smaller amount of yeast.

Will report back in about a week once I do a tasting. Hefes tend to carb up pretty quickly for me.

 

[jjeffers09]

what is your water source?

 

[Sadu]

what is your water source?

I use tap water. It's quite soft and as far as I can tell it's good for brewing since it's low in everything and I can add whatever is needed as per the style I'm brewing.

Calcium 8ppm
Magnesuim 2ppm
Sodium 7ppm
Bicarbonate 36ppm
Sulfate approx 0-10ppm
Chloride 10ppm
Total alkalinity 30

This brew I added a small amount of CaCl2 and Gypsum to bring the Calcuim to 50ppm and keep the Sulfate/Chloride balanced, plus lower the pH a bit. I acidified the sparge with lactic acid to bring it to 6.0 pH and did no acidification of the mash (even though it could have used some).

This tart flavour is very frustrating. It has wrecked 3 batches now. I have assumed that it is the sourmalz/lactic addition, but it only affects hefeweizen / dunkelweizen which include wheat malt and Wyeast 3638 yeast. I have made pale ales & yellow lagers with 2% sourmalz and they taste fantastic. The tart flavour does show up in other styles in the gravity samples, but is gone after a bit of lagering.

I think I need to try a different hefe yeast to rule that out. But I'm also thinking it might be the wheat malt - maybe there is already some tartness in the wheat that the lactic acid brings to the forefront.

 

[Sadu]

I tasted this last night. Because I brew small batches I always have a half-bottle worth at the end, I like to use that as an early sampler to see how carbonation is going. So I tasted 3 half-bottles of hefe after 5 days carbonating. These were primed with a full priming drop each so I didn't want to leave them too long.

I did not taste these blind but I think I would struggle to tell the difference between them at this point. The tart flavour was definitely getting in the way, but other than that the only difference I could pick was some sweetness on the 2ml lowest-pitched version. This is probably from the priming sugar, so nothing conclusive here.

I need to do another tasting once fully carbed but I am starting to draw some conclusions from this experiment. The main ones being that none of these was an underpitch; and the beer tasted pretty bad; so therefore I think the experiment needs to be repeated.

As well as testing pitch rate I need to figure out this tartness problem. So I'll also remove all lactic/sourmalt additions. I and thinking very hard about using a different yeast, either WB-06 which I have or ordering in some 3068 or the popular white labs one. And less yeast next time. Apparently 2 tablespoons per 5 gallons is not an underpitch :rockin:

 

[wischwm]

I'm also subbing in! Interesting experiment. I typically do a 1L starter using WLP300 but often find the banana a little lacking.

 

[TheHopfather]

I'm curious why you have decided that the 2mL batch isn't an under pitch? MrMalty told you that the 7mL batch was the correct pitch rate, anything under that 7mL is an under pitch. Of course the beer is going to ferment, that is what yeast does. The idea with the under pitch is that the "off flavors" created during the growth phase are actually the signature flavors you are shooting for.

Banana flavor in a beer is driven from isoamyl acetate, that is the ester that gives the banana flavor. Under pitching increases ester production, so in theory you are creating the best conditions for isoamyl acetate production. The yeast will still replicate and ferment the wort if under pitched. The only way to tell if your experiment bore fruit is in the final taste of the beer. If you get more banana in the 2mL sample vs. the 7mL sample you can say the under pitch did increase isoamyl acetate production.

If you are looking for clove flavor you need to know those are a phenol, 4-Vinyl guaiacol, which is created by the decarboxylation of ferulic acid. To increase that you want to do a ferulic acid rest during the mash at 113F.

 

[wischwm]

Hopfather, if MrMalty says 7ml's is correct and there's little to no difference in taste between 2ml and 7ml, then I'm with Sadu - it isn't an underpitch. As you've already stated, he should have experienced an increase in the isoamyl acetate response if it were. I'm curious why you responded without reading the entire experiment?

 

[TheHopfather]

I did read the entire thing. By definition an under pitch is anything less than an optimal pitch. You would only consider something an under pitch if it generates off flavors? I think conventional home brewing wisdom would say that an under pitch should/would increase isoamyl acetate, but after reading umpteen Brulosophy experiments, I think it is safe to say conventional home brewing wisdom isn't always correct.

I'm not trying to take anything away from the experiment, I think it is very interesting. I am genuinely interested in the results, I was actually curious why the OP decided the 2mL pitch wasn't under pitching.

The take away to me would be that under pitching Bavarian yeasts, or at least 3638, doesn't lead to a noticeable increase of isoamyl acetate. Not that the yeast wasn't under pitched.

 

[Sadu]

I'm curious why you have decided that the 2mL batch isn't an under pitch?

It's an interesting point you make.

This is what is driving my conclusion...
- Airlock activity and good krausen at 19 hours.
- At FG by 4 days or earlier.
- All 3 samples taste the same.

On the other hand...
- Any taste differences could be hidden by the lactic off-flavour.
- The tasting was done on incomplete carbonation with residual priming sugar in the bottle.

I need to do another taste once properly carbonated (this weekend) so I can properly assess, maybe get a friend involved too. But I definitely expected a longer lag time and a slower fermentation from the underpitch.

What probably happened is that my yeast is very healthy and I estimated the cell density incorrectly. I told MrMalty 2.5b cells/ml with 10% non-yeast matter which is what I have been doing to date - however I have always tried to err on the side of overpitching, especially with lagers.

But let's say I slide MrMalty all the way to 4.5b cells/ml that would make the 4ml version the "correct" pitch and the 2ml version still a 50% underpitch.

What I find fascinating is that the low-pitched version works out at 30ml or 2 tablespoons per 5 gallon batch. It just seems like such a tiny amount, I would never normally pitch this little, and yet no evidence of stressed yeast?