Yeast Starters and Building a Quick/Dirty GhettoBlasting Stir Plate

Yeast StarterOne thing you might hear about as you get further along into homebrewing is the need for a “yeast starter” or “pitching rates.”  Below 1.060 gravity you can still get away with a single smackpack or vial of yeast and end up with a fermentation that finishes and has enough oomph to clean itself up afterwards.  But when you start looking into big Imperial style beers, barley/wheat wines, Double IPAs, etc a single serving of liquid yeast is simply not enough yeast to finish off such a big plate of sugar.  So now we need to make a starter!

erlenmeyer_small_For a typical big beer between 1.060-80 you will need at least a 1-Liter Erlenmeyer flask and you will need some DME (Dry Malt Extract) and you will need to brew up the DME for 1.040 of yeast starter goodness.  You need about 10g of DME per 100mL of starter so 1L will come in at 3.5 oz of DME boiled in 1L of water for about 15-20 minutes.  What I like to do is get the water boiling in the Erlenmeyer flask to sanitize it and then carefully pour the boiling water into a saucepan and boil the wort with the DME.  Once you have boiled the wort pour it back into the Erlenmeyer flask and chill it down like you would if you were brewing a small beer.  An ice bath in the sink will suffice.  This is why I put the wort back into the flask because I have found that the flask fits easier in the sink than a saucepan with a handle.

Once the wort is cool go ahead and pitch your yeast into the wort and allow 24-36 hours for the yeast to have reached their maximum population for the volume of wort given.  Aerate the wort as you would normally as well and place enough aluminium foil over the top to cover the flask but do not make the container airtight.  The yeast require that oxygen to grow optimally for the next 24 hours. Also keep in mind that increasing the gravity WILL NOT increase yeast count. It will only increase stress.  Less gravity will have a negative impact on yeast growth however so 1.040 is found to be a “sweet spot” so to speak.  Creating this starter will typically increase the number of cells from a pack/vial of 100 billion to 130-150 billion cells for a 1L starter.  Again, as I said if you need more cells you can go with a 2L starter and get ~180-200 billion cells.  Brewing a 1.110 OG barleywine and need about 350 billion yeast cells you say?  Well, that is where the stir plate comes in!
A stir plate will actually DOUBLE your yeast cell count from a non-agitated yeast starter.  So your 1L starter that produces 135 billion cells will jump to about 260 billion cells if properly agitated for 24-36 hours.  Agitation is a process that keeps the yeast cells from flocculating out of suspension, which also inhibits their continued growth.

You can spend upwards of $100 for a cheap stir plate or even more for a professional agitation unit OR…. You can build your own for anywhere between $15-30.

I just recently built one using this video as inspiration:

The one place where my build differs from Fo’s is I used a Thermaltake Mobile Fan II External USB cooling fan for the magnet mount.  This somewhat limits where I can plug in my stir plate as I don’t have a laptop but I didn’t feel like splicing the wire.  Splicing wire is not hard at all but I’m lazy and just felt like going the USB route and it works great.  Make sure you have a variable control for your fan RPM however.  When you first plug in/turn on your stir plate with your suspension in place the bar may not move right away and you will need to slowly increase the rate of spin to get it turning, taking care not to “throw” the stir bar.  Once the bar is turning you can then turn down the RPM if you so choose or leave it where it is.  As far as I know the speed at which the bar is spinning has little to no effect on the actual process.  So long as you are agitating the yeast cells and keeping them from flocculating and settling out, your stir plate is doing its job.

Here are some before/after screenshots from Beersmith showing its calculated difference between using a stir plate and NOT using a stir plate:
noSP_small_zpseac6bdf3No Stir Plate

yesSPsmall_zps5ed5d3db With Stir Plate

That is about it.  Here is a quick video of my own build in action:
I purchased the fan and stir bar on Amazon, the project box and magnets were purchased from my local Radioshack, and the mountings for the fan/variable control were purchased at Lowe’s. If you have any questions or comments feel free to email me or comment on this article.  Thanks for reading!

Pear Cider in 5 Easy Steps!

Pear Cider - 01

Making pear cider is not as hard as it may sound. If you are comfortable brewing beer, you should have no problem making a good cider. As will all things fermented, remember that sanitation is key. I’ve compiled an easy step by step set of instructions for making cider from organic pear fruit juice. Here is a list of what you will need for a 5 gallon batch:

1 – 6.5 gallon carboy/food grade bucket w/ airlock or blowoff hose
1 – Small sanitized funnel
5 – Gallons of organic pear juice. (I’ve used R. W. Knudsen’s Organic Pear Juice)
1 – Package of yeast (I’ve used Wyeast Labs 4184 Sweet Mead Yeast)
1/2 – tsp of Yeast Nutrient
2 1/2 – tsp of Pectic Enzyme (Settles out free floating pectin in pasteurized juice, and will help you clarify improve your cider yield)
1/4 – tsp Potassium Metabisulphite (to kill of any wild yeast if using unpasteurized/ juice)
Brown sugar
1/2 tsp of Potassium Sorbate

Step 1: Make sure that your carboy/bucket is sanitized. I usually do a wash and scrub with unscented Oxyclean or PBW, a double water rinse, and then sanitize it with a no rinse acid based sanitizer like Star San. This step is very important because we will not be boiling the juice like we would wort in brewing beer. I activate my yeast packet in the morning and let it sit while I clean my equipment. Take your time! Give your yeast at least a few hours to reproduce before pitching it into your juice.

Pear Cider - 02

Step 2: Once your yeast is ready to go, portion out your ingredients and get them ready to go. Make sure that your measuring spoons are clean and sanitized as well. Start pouring your juice into the fermenter. I usually pour off half of the juice, and then add the yeast nutrient, pectic enzyme, potassium metabisulphite, and any additional sugar to the remaining juice in it’s container so I can shake them together. This allows the ingredients to dissolve into the juice before adding it to the fermenter. If you are using pasteurized juice (which most of you will likely be using for this recipe), it will be cloudy. The pectic enzyme will help break down the free floating pectin in your juice, which will remove the haze from your finished product. Another thing to note is that the Original Specific Gravity of your juice should be at around 1.050. If it is not, you can add 2.25 oz of brown sugar or 3 oz honey per gallon to raise the OSG by increments of .005. A solid 1.060 OSG will yield between 7 to 9% abv with cider/mead yeast.

Pear Cider - 03

Step 3: Once all of your juice has been added to the fermenter, immediately pitch your yeast and aerate your batch. Providing the yeast with plenty of oxygen will help promote healthy yeast cell walls, which in turn will allow your yeast to propagate through your juice quickly. This will reduce fermentation lag time, and decrease your chance of bacterial infection. As you can see from the picture, I inject oxygen using an oxygen regulator and difuser stone.

Step 4: Allow your cider to ferment for 7-10 days. Once fermentation has ceased you can cold crash your batch or move it to a secondary for clarification. I would suggest letting your cider at sit least a week to allow yeast and unfermentables to settle out. Store bought juice is pasteurized, which naturally creates a large amount of pectin in the juice. The pectic enzyme added in Step 2 is critical if you want clear, non-cloudy cider.

Step 5: Dissolve 1/4 tsp of Potassium Metabisulphite and a 1/2 tsp of Potassium Sorbate into your batch. This “shuts off” your yeast activity and allows you to back sweeten your cider (which will be dry and tart) with more juice, brown sugar, or honey to taste. From here you should keg.

We at BIMP have made some outstanding cider using this method. It works great with any organic juice you can buy at the store. Please post any comments or recipe suggestions below. Enjoy!